/*
 * Terminal emulator.
 */

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <limits.h>

#include <time.h>
#include <assert.h>
#include "putty.h"
#include "terminal.h"

// region tray-url
#include "urlhack.h"
// endregion

#define poslt(p1, p2) ((p1).y < (p2).y || ((p1).y == (p2).y && (p1).x < (p2).x))
#define posle(p1, p2)                                                          \
  ((p1).y < (p2).y || ((p1).y == (p2).y && (p1).x <= (p2).x))
#define poseq(p1, p2) ((p1).y == (p2).y && (p1).x == (p2).x)
#define posdiff(p1, p2) (((p1).y - (p2).y) * (term->cols + 1) + (p1).x - (p2).x)

/* Product-order comparisons for rectangular block selection. */
#define posPlt(p1, p2) ((p1).y <= (p2).y && (p1).x < (p2).x)
#define posPle(p1, p2) ((p1).y <= (p2).y && (p1).x <= (p2).x)

#define incpos(p) ((p).x == term->cols ? ((p).x = 0, (p).y++, 1) : ((p).x++, 0))
#define decpos(p) ((p).x == 0 ? ((p).x = term->cols, (p).y--, 1) : ((p).x--, 0))

#define VT52_PLUS

#define CL_ANSIMIN 0x0001   /* Codes in all ANSI like terminals. */
#define CL_VT100 0x0002     /* VT100 */
#define CL_VT100AVO 0x0004  /* VT100 +AVO; 132x24 (not 132x14) & attrs */
#define CL_VT102 0x0008     /* VT102 */
#define CL_VT220 0x0010     /* VT220 */
#define CL_VT320 0x0020     /* VT320 */
#define CL_VT420 0x0040     /* VT420 */
#define CL_VT510 0x0080     /* VT510, NB VT510 includes ANSI */
#define CL_VT340TEXT 0x0100 /* VT340 extensions that appear in the VT420 */
#define CL_SCOANSI 0x1000   /* SCOANSI not in ANSIMIN. */
#define CL_ANSI 0x2000      /* ANSI ECMA-48 not in the VT100..VT420 */
#define CL_OTHER 0x4000     /* Others, Xterm, linux, putty, dunno, etc */

#define TM_VT100 (CL_ANSIMIN | CL_VT100)
#define TM_VT100AVO (TM_VT100 | CL_VT100AVO)
#define TM_VT102 (TM_VT100AVO | CL_VT102)
#define TM_VT220 (TM_VT102 | CL_VT220)
#define TM_VTXXX (TM_VT220 | CL_VT340TEXT | CL_VT510 | CL_VT420 | CL_VT320)
#define TM_SCOANSI (CL_ANSIMIN | CL_SCOANSI)

#define TM_PUTTY (0xFFFF)

#define UPDATE_DELAY                                                           \
  ((TICKSPERSEC + 49) / 50) /* ticks to defer window update */
#define TBLINK_DELAY                                                           \
  ((TICKSPERSEC * 9 + 19) / 20)     /* ticks between text blinks*/
#define CBLINK_DELAY (CURSORBLINK)  /* ticks between cursor blinks */
#define VBELL_DELAY (VBELL_TIMEOUT) /* visual bell timeout in ticks */

#define compatibility(x)                                                       \
  if (((CL_##x) & term->compatibility_level) == 0) {                           \
    term->termstate = TOPLEVEL;                                                \
    break;                                                                     \
  }
#define compatibility2(x, y)                                                   \
  if (((CL_##x | CL_##y) & term->compatibility_level) == 0) {                  \
    term->termstate = TOPLEVEL;                                                \
    break;                                                                     \
  }

#define has_compat(x) (((CL_##x) & term->compatibility_level) != 0)

const char *EMPTY_WINDOW_TITLE = "";

const char sco2ansicolour[] = {0, 4, 2, 6, 1, 5, 3, 7};

#define sel_nl_sz (sizeof(sel_nl) / sizeof(wchar_t))
const wchar_t sel_nl[] = SEL_NL;

/*
 * Fetch the character at a particular position in a line array,
 * for purposes of `wordtype'. The reason this isn't just a simple
 * array reference is that if the character we find is UCSWIDE,
 * then we must look one space further to the left.
 */
#define UCSGET(a, x)                                                           \
  ((x) > 0 && (a)[(x)].chr == UCSWIDE ? (a)[(x)-1].chr : (a)[(x)].chr)

/*
 * Detect the various aliases of U+0020 SPACE.
 */
#define IS_SPACE_CHR(chr)                                                      \
  ((chr) == 0x20 || (DIRECT_CHAR(chr) && ((chr)&0xFF) == 0x20))

/*
 * Spot magic CSETs.
 */
#define CSET_OF(chr)                                                           \
  (DIRECT_CHAR(chr) || DIRECT_FONT(chr) ? (chr)&CSET_MASK : 0)

/*
 * Internal prototypes.
 */
static void resizeline(Terminal *, termline *, int);
static termline *lineptr(Terminal *, int, int, int);
static void unlineptr(termline *);
static void check_line_size(Terminal *, termline *);
static void do_paint(Terminal *, Context, int);
static void erase_lots(Terminal *, int, int, int);
static int find_last_nonempty_line(Terminal *, tree234 *);
static void swap_screen(Terminal *, int, int, int);
static void update_sbar(Terminal *);
static void deselect(Terminal *);
static void term_print_finish(Terminal *);
static void scroll(Terminal *, int, int, int, int);
#ifdef OPTIMISE_SCROLL
static void scroll_display(Terminal *, int, int, int);
#endif /* OPTIMISE_SCROLL */

static termline *newline(Terminal *term, int cols, int bce)
{
  termline *line;
  int j;

  line = snew(termline);
  line->chars = snewn(cols, termchar);
  for (j = 0; j < cols; j++)
    line->chars[j] = (bce ? term->erase_char : term->basic_erase_char);
  line->cols = line->size = cols;
  line->lattr = LATTR_NORM;
  line->temporary = FALSE;
  line->cc_free = 0;

  return line;
}

static void freeline(termline *line)
{
  if (line) {
    sfree(line->chars);
    sfree(line);
  }
}

static void unlineptr(termline *line)
{
  if (line->temporary)
    freeline(line);
}

#ifdef TERM_CC_DIAGS
/*
 * Diagnostic function: verify that a termline has a correct
 * combining character structure.
 *
 * This is a performance-intensive check, so it's no longer enabled
 * by default.
 */
static void cc_check(termline *line)
{
  unsigned char *flags;
  int i, j;

  assert(line->size >= line->cols);

  flags = snewn(line->size, unsigned char);

  for (i = 0; i < line->size; i++)
    flags[i] = (i < line->cols);

  for (i = 0; i < line->cols; i++) {
    j = i;
    while (line->chars[j].cc_next) {
      j += line->chars[j].cc_next;
      assert(j >= line->cols && j < line->size);
      assert(!flags[j]);
      flags[j] = TRUE;
    }
  }

  j = line->cc_free;
  if (j) {
    while (1) {
      assert(j >= line->cols && j < line->size);
      assert(!flags[j]);
      flags[j] = TRUE;
      if (line->chars[j].cc_next)
        j += line->chars[j].cc_next;
      else
        break;
    }
  }

  j = 0;
  for (i = 0; i < line->size; i++)
    j += (flags[i] != 0);

  assert(j == line->size);

  sfree(flags);
}
#endif

/*
 * Add a combining character to a character cell.
 */
static void add_cc(termline *line, int col, unsigned long chr)
{
  int newcc;

  assert(col >= 0 && col < line->cols);

  /*
   * Start by extending the cols array if the free list is empty.
   */
  if (!line->cc_free) {
    int n = line->size;
    line->size += 16 + (line->size - line->cols) / 2;
    line->chars = sresize(line->chars, line->size, termchar);
    line->cc_free = n;
    while (n < line->size) {
      if (n + 1 < line->size)
        line->chars[n].cc_next = 1;
      else
        line->chars[n].cc_next = 0;
      n++;
    }
  }

  /*
   * Now walk the cc list of the cell in question.
   */
  while (line->chars[col].cc_next)
    col += line->chars[col].cc_next;

  /*
   * `col' now points at the last cc currently in this cell; so
   * we simply add another one.
   */
  newcc = line->cc_free;
  if (line->chars[newcc].cc_next)
    line->cc_free = newcc + line->chars[newcc].cc_next;
  else
    line->cc_free = 0;
  line->chars[newcc].cc_next = 0;
  line->chars[newcc].chr = chr;
  line->chars[col].cc_next = newcc - col;

#ifdef TERM_CC_DIAGS
  cc_check(line);
#endif
}

/*
 * Clear the combining character list in a character cell.
 */
static void clear_cc(termline *line, int col)
{
  int oldfree, origcol = col;

  assert(col >= 0 && col < line->cols);

  if (!line->chars[col].cc_next)
    return; /* nothing needs doing */

  oldfree = line->cc_free;
  line->cc_free = col + line->chars[col].cc_next;
  while (line->chars[col].cc_next)
    col += line->chars[col].cc_next;
  if (oldfree)
    line->chars[col].cc_next = oldfree - col;
  else
    line->chars[col].cc_next = 0;

  line->chars[origcol].cc_next = 0;

#ifdef TERM_CC_DIAGS
  cc_check(line);
#endif
}

/*
 * Compare two character cells for equality. Special case required
 * in do_paint() where we override what we expect the chr and attr
 * fields to be.
 */
static int termchars_equal_override(termchar *a,
                                    termchar *b,
                                    unsigned long bchr,
                                    unsigned long battr)
{
  /* FULL-TERMCHAR */
  if (a->chr != bchr)
    return FALSE;
  if ((a->attr & ~DATTR_MASK) != (battr & ~DATTR_MASK))
    return FALSE;
  while (a->cc_next || b->cc_next) {
    if (!a->cc_next || !b->cc_next)
      return FALSE; /* one cc-list ends, other does not */
    a += a->cc_next;
    b += b->cc_next;
    if (a->chr != b->chr)
      return FALSE;
  }
  return TRUE;
}

static int termchars_equal(termchar *a, termchar *b)
{
  return termchars_equal_override(a, b, b->chr, b->attr);
}

/*
 * Copy a character cell. (Requires a pointer to the destination
 * termline, so as to access its free list.)
 */
static void copy_termchar(termline *destline, int x, termchar *src)
{
  clear_cc(destline, x);

  destline->chars[x] = *src;      /* copy everything except cc-list */
  destline->chars[x].cc_next = 0; /* and make sure this is zero */

  while (src->cc_next) {
    src += src->cc_next;
    add_cc(destline, x, src->chr);
  }

#ifdef TERM_CC_DIAGS
  cc_check(destline);
#endif
}

/*
 * Move a character cell within its termline.
 */
static void move_termchar(termline *line, termchar *dest, termchar *src)
{
  /* First clear the cc list from the original char, just in case. */
  clear_cc(line, dest - line->chars);

  /* Move the character cell and adjust its cc_next. */
  *dest = *src; /* copy everything except cc-list */
  if (src->cc_next)
    dest->cc_next = src->cc_next - (dest - src);

  /* Ensure the original cell doesn't have a cc list. */
  src->cc_next = 0;

#ifdef TERM_CC_DIAGS
  cc_check(line);
#endif
}

/*
 * Compress and decompress a termline into an RLE-based format for
 * storing in scrollback. (Since scrollback almost never needs to
 * be modified and exists in huge quantities, this is a sensible
 * tradeoff, particularly since it allows us to continue adding
 * features to the main termchar structure without proportionally
 * bloating the terminal emulator's memory footprint unless those
 * features are in constant use.)
 */
struct buf {
  unsigned char *data;
  int len, size;
};
static void add(struct buf *b, unsigned char c)
{
  if (b->len >= b->size) {
    b->size = (b->len * 3 / 2) + 512;
    b->data = sresize(b->data, b->size, unsigned char);
  }
  b->data[b->len++] = c;
}
static int get(struct buf *b)
{
  return b->data[b->len++];
}
static void makerle(struct buf *b,
                    termline *ldata,
                    void (*makeliteral)(struct buf *b,
                                        termchar *c,
                                        unsigned long *state))
{
  int hdrpos, hdrsize, n, prevlen, prevpos, thislen, thispos, prev2;
  termchar *c = ldata->chars;
  unsigned long state = 0, oldstate;

  n = ldata->cols;

  hdrpos = b->len;
  hdrsize = 0;
  add(b, 0);
  prevlen = prevpos = 0;
  prev2 = FALSE;

  while (n-- > 0) {
    thispos = b->len;
    makeliteral(b, c++, &state);
    thislen = b->len - thispos;
    if (thislen == prevlen &&
        !memcmp(b->data + prevpos, b->data + thispos, thislen)) {
      /*
       * This literal precisely matches the previous one.
       * Turn it into a run if it's worthwhile.
       *
       * With one-byte literals, it costs us two bytes to
       * encode a run, plus another byte to write the header
       * to resume normal output; so a three-element run is
       * neutral, and anything beyond that is unconditionally
       * worthwhile. With two-byte literals or more, even a
       * 2-run is a win.
       */
      if (thislen > 1 || prev2) {
        int runpos, runlen;

        /*
         * It's worth encoding a run. Start at prevpos,
         * unless hdrsize==0 in which case we can back up
         * another one and start by overwriting hdrpos.
         */

        hdrsize--; /* remove the literal at prevpos */
        if (prev2) {
          assert(hdrsize > 0);
          hdrsize--;
          prevpos -= prevlen; /* and possibly another one */
        }

        if (hdrsize == 0) {
          assert(prevpos == hdrpos + 1);
          runpos = hdrpos;
          b->len = prevpos + prevlen;
        } else {
          memmove(b->data + prevpos + 1, b->data + prevpos, prevlen);
          runpos = prevpos;
          b->len = prevpos + prevlen + 1;
          /*
           * Terminate the previous run of ordinary
           * literals.
           */
          assert(hdrsize >= 1 && hdrsize <= 128);
          b->data[hdrpos] = hdrsize - 1;
        }

        runlen = prev2 ? 3 : 2;

        while (n > 0 && runlen < 129) {
          int tmppos, tmplen;
          tmppos = b->len;
          oldstate = state;
          makeliteral(b, c, &state);
          tmplen = b->len - tmppos;
          b->len = tmppos;
          if (tmplen != thislen ||
              memcmp(b->data + runpos + 1, b->data + tmppos, tmplen)) {
            state = oldstate;
            break; /* run over */
          }
          n--, c++, runlen++;
        }

        assert(runlen >= 2 && runlen <= 129);
        b->data[runpos] = runlen + 0x80 - 2;

        hdrpos = b->len;
        hdrsize = 0;
        add(b, 0);
        /* And ensure this run doesn't interfere with the next. */
        prevlen = prevpos = 0;
        prev2 = FALSE;

        continue;
      } else {
        /*
         * Just flag that the previous two literals were
         * identical, in case we find a third identical one
         * we want to turn into a run.
         */
        prev2 = TRUE;
        prevlen = thislen;
        prevpos = thispos;
      }
    } else {
      prev2 = FALSE;
      prevlen = thislen;
      prevpos = thispos;
    }

    /*
     * This character isn't (yet) part of a run. Add it to
     * hdrsize.
     */
    hdrsize++;
    if (hdrsize == 128) {
      b->data[hdrpos] = hdrsize - 1;
      hdrpos = b->len;
      hdrsize = 0;
      add(b, 0);
      prevlen = prevpos = 0;
      prev2 = FALSE;
    }
  }

  /*
   * Clean up.
   */
  if (hdrsize > 0) {
    assert(hdrsize <= 128);
    b->data[hdrpos] = hdrsize - 1;
  } else {
    b->len = hdrpos;
  }
}
static void makeliteral_chr(struct buf *b, termchar *c, unsigned long *state)
{
  /*
   * My encoding for characters is UTF-8-like, in that it stores
   * 7-bit ASCII in one byte and uses high-bit-set bytes as
   * introducers to indicate a longer sequence. However, it's
   * unlike UTF-8 in that it doesn't need to be able to
   * resynchronise, and therefore I don't want to waste two bits
   * per byte on having recognisable continuation characters.
   * Also I don't want to rule out the possibility that I may one
   * day use values 0x80000000-0xFFFFFFFF for interesting
   * purposes, so unlike UTF-8 I need a full 32-bit range.
   * Accordingly, here is my encoding:
   *
   * 00000000-0000007F: 0xxxxxxx (but see below)
   * 00000080-00003FFF: 10xxxxxx xxxxxxxx
   * 00004000-001FFFFF: 110xxxxx xxxxxxxx xxxxxxxx
   * 00200000-0FFFFFFF: 1110xxxx xxxxxxxx xxxxxxxx xxxxxxxx
   * 10000000-FFFFFFFF: 11110ZZZ xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx
   *
   * (`Z' is like `x' but is always going to be zero since the
   * values I'm encoding don't go above 2^32. In principle the
   * five-byte form of the encoding could extend to 2^35, and
   * there could be six-, seven-, eight- and nine-byte forms as
   * well to allow up to 64-bit values to be encoded. But that's
   * completely unnecessary for these purposes!)
   *
   * The encoding as written above would be very simple, except
   * that 7-bit ASCII can occur in several different ways in the
   * terminal data; sometimes it crops up in the D800 page
   * (CSET_ASCII) but at other times it's in the 0000 page (real
   * Unicode). Therefore, this encoding is actually _stateful_:
   * the one-byte encoding of 00-7F actually indicates `reuse the
   * upper three bytes of the last character', and to encode an
   * absolute value of 00-7F you need to use the two-byte form
   * instead.
   */
  if ((c->chr & ~0x7F) == *state) {
    add(b, (unsigned char)(c->chr & 0x7F));
  } else if (c->chr < 0x4000) {
    add(b, (unsigned char)(((c->chr >> 8) & 0x3F) | 0x80));
    add(b, (unsigned char)(c->chr & 0xFF));
  } else if (c->chr < 0x200000) {
    add(b, (unsigned char)(((c->chr >> 16) & 0x1F) | 0xC0));
    add(b, (unsigned char)((c->chr >> 8) & 0xFF));
    add(b, (unsigned char)(c->chr & 0xFF));
  } else if (c->chr < 0x10000000) {
    add(b, (unsigned char)(((c->chr >> 24) & 0x0F) | 0xE0));
    add(b, (unsigned char)((c->chr >> 16) & 0xFF));
    add(b, (unsigned char)((c->chr >> 8) & 0xFF));
    add(b, (unsigned char)(c->chr & 0xFF));
  } else {
    add(b, 0xF0);
    add(b, (unsigned char)((c->chr >> 24) & 0xFF));
    add(b, (unsigned char)((c->chr >> 16) & 0xFF));
    add(b, (unsigned char)((c->chr >> 8) & 0xFF));
    add(b, (unsigned char)(c->chr & 0xFF));
  }
  *state = c->chr & ~0xFF;
}
static void makeliteral_attr(struct buf *b, termchar *c, unsigned long *state)
{
  /*
   * My encoding for attributes is 16-bit-granular and assumes
   * that the top bit of the word is never required. I either
   * store a two-byte value with the top bit clear (indicating
   * just that value), or a four-byte value with the top bit set
   * (indicating the same value with its top bit clear).
   *
   * However, first I permute the bits of the attribute value, so
   * that the eight bits of colour (four in each of fg and bg)
   * which are never non-zero unless xterm 256-colour mode is in
   * use are placed higher up the word than everything else. This
   * ensures that attribute values remain 16-bit _unless_ the
   * user uses extended colour.
   */
  unsigned attr, colourbits;

  attr = c->attr;

  assert(ATTR_BGSHIFT > ATTR_FGSHIFT);

  colourbits = (attr >> (ATTR_BGSHIFT + 4)) & 0xF;
  colourbits <<= 4;
  colourbits |= (attr >> (ATTR_FGSHIFT + 4)) & 0xF;

  attr = (((attr >> (ATTR_BGSHIFT + 8)) << (ATTR_BGSHIFT + 4)) |
          (attr & ((1 << (ATTR_BGSHIFT + 4)) - 1)));
  attr = (((attr >> (ATTR_FGSHIFT + 8)) << (ATTR_FGSHIFT + 4)) |
          (attr & ((1 << (ATTR_FGSHIFT + 4)) - 1)));

  attr |= (colourbits << (32 - 9));

  if (attr < 0x8000) {
    add(b, (unsigned char)((attr >> 8) & 0xFF));
    add(b, (unsigned char)(attr & 0xFF));
  } else {
    add(b, (unsigned char)(((attr >> 24) & 0x7F) | 0x80));
    add(b, (unsigned char)((attr >> 16) & 0xFF));
    add(b, (unsigned char)((attr >> 8) & 0xFF));
    add(b, (unsigned char)(attr & 0xFF));
  }
}
static void makeliteral_cc(struct buf *b, termchar *c, unsigned long *state)
{
  /*
   * For combining characters, I just encode a bunch of ordinary
   * chars using makeliteral_chr, and terminate with a \0
   * character (which I know won't come up as a combining char
   * itself).
   *
   * I don't use the stateful encoding in makeliteral_chr.
   */
  unsigned long zstate;
  termchar z;

  while (c->cc_next) {
    c += c->cc_next;

    assert(c->chr != 0);

    zstate = 0;
    makeliteral_chr(b, c, &zstate);
  }

  z.chr = 0;
  zstate = 0;
  makeliteral_chr(b, &z, &zstate);
}

static termline *decompressline(unsigned char *data, int *bytes_used);

static unsigned char *compressline(termline *ldata)
{
  struct buf buffer = {NULL, 0, 0}, *b = &buffer;

  /*
   * First, store the column count, 7 bits at a time, least
   * significant `digit' first, with the high bit set on all but
   * the last.
   */
  {
    int n = ldata->cols;
    while (n >= 128) {
      add(b, (unsigned char)((n & 0x7F) | 0x80));
      n >>= 7;
    }
    add(b, (unsigned char)(n));
  }

  /*
   * Next store the lattrs; same principle.
   */
  {
    int n = ldata->lattr;
    while (n >= 128) {
      add(b, (unsigned char)((n & 0x7F) | 0x80));
      n >>= 7;
    }
    add(b, (unsigned char)(n));
  }

  /*
   * Now we store a sequence of separate run-length encoded
   * fragments, each containing exactly as many symbols as there
   * are columns in the ldata.
   *
   * All of these have a common basic format:
   *
   *  - a byte 00-7F indicates that X+1 literals follow it
   * 	- a byte 80-FF indicates that a single literal follows it
   * 	  and expects to be repeated (X-0x80)+2 times.
   *
   * The format of the `literals' varies between the fragments.
   */
  makerle(b, ldata, makeliteral_chr);
  makerle(b, ldata, makeliteral_attr);
  makerle(b, ldata, makeliteral_cc);

  /*
   * Diagnostics: ensure that the compressed data really does
   * decompress to the right thing.
   *
   * This is a bit performance-heavy for production code.
   */
#ifdef TERM_CC_DIAGS
#ifndef CHECK_SB_COMPRESSION
  {
    int dused;
    termline *dcl;
    int i;

#ifdef DIAGNOSTIC_SB_COMPRESSION
    for (i = 0; i < b->len; i++) {
      printf(" %02x ", b->data[i]);
    }
    printf("\n");
#endif

    dcl = decompressline(b->data, &dused);
    assert(b->len == dused);
    assert(ldata->cols == dcl->cols);
    assert(ldata->lattr == dcl->lattr);
    for (i = 0; i < ldata->cols; i++)
      assert(termchars_equal(&ldata->chars[i], &dcl->chars[i]));

#ifdef DIAGNOSTIC_SB_COMPRESSION
    printf("%d cols (%d bytes) -> %d bytes (factor of %g)\n",
           ldata->cols,
           4 * ldata->cols,
           dused,
           (double)dused / (4 * ldata->cols));
#endif

    freeline(dcl);
  }
#endif
#endif /* TERM_CC_DIAGS */

  /*
   * Trim the allocated memory so we don't waste any, and return.
   */
  return sresize(b->data, b->len, unsigned char);
}

static void readrle(struct buf *b,
                    termline *ldata,
                    void (*readliteral)(struct buf *b,
                                        termchar *c,
                                        termline *ldata,
                                        unsigned long *state))
{
  int n = 0;
  unsigned long state = 0;

  while (n < ldata->cols) {
    int hdr = get(b);

    if (hdr >= 0x80) {
      /* A run. */

      int pos = b->len, count = hdr + 2 - 0x80;
      while (count--) {
        assert(n < ldata->cols);
        b->len = pos;
        readliteral(b, ldata->chars + n, ldata, &state);
        n++;
      }
    } else {
      /* Just a sequence of consecutive literals. */

      int count = hdr + 1;
      while (count--) {
        assert(n < ldata->cols);
        readliteral(b, ldata->chars + n, ldata, &state);
        n++;
      }
    }
  }

  assert(n == ldata->cols);
}
static void readliteral_chr(struct buf *b,
                            termchar *c,
                            termline *ldata,
                            unsigned long *state)
{
  int byte;

  /*
   * 00000000-0000007F: 0xxxxxxx
   * 00000080-00003FFF: 10xxxxxx xxxxxxxx
   * 00004000-001FFFFF: 110xxxxx xxxxxxxx xxxxxxxx
   * 00200000-0FFFFFFF: 1110xxxx xxxxxxxx xxxxxxxx xxxxxxxx
   * 10000000-FFFFFFFF: 11110ZZZ xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx
   */

  byte = get(b);
  if (byte < 0x80) {
    c->chr = byte | *state;
  } else if (byte < 0xC0) {
    c->chr = (byte & ~0xC0) << 8;
    c->chr |= get(b);
  } else if (byte < 0xE0) {
    c->chr = (byte & ~0xE0) << 16;
    c->chr |= get(b) << 8;
    c->chr |= get(b);
  } else if (byte < 0xF0) {
    c->chr = (byte & ~0xF0) << 24;
    c->chr |= get(b) << 16;
    c->chr |= get(b) << 8;
    c->chr |= get(b);
  } else {
    assert(byte == 0xF0);
    c->chr = get(b) << 24;
    c->chr |= get(b) << 16;
    c->chr |= get(b) << 8;
    c->chr |= get(b);
  }
  *state = c->chr & ~0xFF;
}
static void readliteral_attr(struct buf *b,
                             termchar *c,
                             termline *ldata,
                             unsigned long *state)
{
  unsigned val, attr, colourbits;

  val = get(b) << 8;
  val |= get(b);

  if (val >= 0x8000) {
    val &= ~0x8000;
    val <<= 16;
    val |= get(b) << 8;
    val |= get(b);
  }

  colourbits = (val >> (32 - 9)) & 0xFF;
  attr = (val & ((1 << (32 - 9)) - 1));

  attr = (((attr >> (ATTR_FGSHIFT + 4)) << (ATTR_FGSHIFT + 8)) |
          (attr & ((1 << (ATTR_FGSHIFT + 4)) - 1)));
  attr = (((attr >> (ATTR_BGSHIFT + 4)) << (ATTR_BGSHIFT + 8)) |
          (attr & ((1 << (ATTR_BGSHIFT + 4)) - 1)));

  attr |= (colourbits >> 4) << (ATTR_BGSHIFT + 4);
  attr |= (colourbits & 0xF) << (ATTR_FGSHIFT + 4);

  c->attr = attr;
}
static void readliteral_cc(struct buf *b,
                           termchar *c,
                           termline *ldata,
                           unsigned long *state)
{
  termchar n;
  unsigned long zstate;
  int x = c - ldata->chars;

  c->cc_next = 0;

  while (1) {
    zstate = 0;
    readliteral_chr(b, &n, ldata, &zstate);
    if (!n.chr)
      break;
    add_cc(ldata, x, n.chr);
  }
}

static termline *decompressline(unsigned char *data, int *bytes_used)
{
  int ncols, byte, shift;
  struct buf buffer, *b = &buffer;
  termline *ldata;

  b->data = data;
  b->len = 0;

  /*
   * First read in the column count.
   */
  ncols = shift = 0;
  do {
    byte = get(b);
    ncols |= (byte & 0x7F) << shift;
    shift += 7;
  } while (byte & 0x80);

  /*
   * Now create the output termline.
   */
  ldata = snew(termline);
  ldata->chars = snewn(ncols, termchar);
  ldata->cols = ldata->size = ncols;
  ldata->temporary = TRUE;
  ldata->cc_free = 0;

  /*
   * We must set all the cc pointers in ldata->chars to 0 right
   * now, so that cc diagnostics that verify the integrity of the
   * whole line will make sense while we're in the middle of
   * building it up.
   */
  {
    int i;
    for (i = 0; i < ldata->cols; i++)
      ldata->chars[i].cc_next = 0;
  }

  /*
   * Now read in the lattr.
   */
  ldata->lattr = shift = 0;
  do {
    byte = get(b);
    ldata->lattr |= (byte & 0x7F) << shift;
    shift += 7;
  } while (byte & 0x80);

  /*
   * Now we read in each of the RLE streams in turn.
   */
  readrle(b, ldata, readliteral_chr);
  readrle(b, ldata, readliteral_attr);
  readrle(b, ldata, readliteral_cc);

  /* Return the number of bytes read, for diagnostic purposes. */
  if (bytes_used)
    *bytes_used = b->len;

  return ldata;
}

/*
 * Resize a line to make it `cols' columns wide.
 */
static void resizeline(Terminal *term, termline *line, int cols)
{
  int i, oldcols;

  if (line->cols != cols) {

    oldcols = line->cols;

    /*
     * This line is the wrong length, which probably means it
     * hasn't been accessed since a resize. Resize it now.
     *
     * First, go through all the characters that will be thrown
     * out in the resize (if we're shrinking the line) and
     * return their cc lists to the cc free list.
     */
    for (i = cols; i < oldcols; i++)
      clear_cc(line, i);

    /*
     * If we're shrinking the line, we now bodily move the
     * entire cc section from where it started to where it now
     * needs to be. (We have to do this before the resize, so
     * that the data we're copying is still there. However, if
     * we're expanding, we have to wait until _after_ the
     * resize so that the space we're copying into is there.)
     */
    if (cols < oldcols)
      memmove(line->chars + cols,
              line->chars + oldcols,
              (line->size - line->cols) * TSIZE);

    /*
     * Now do the actual resize, leaving the _same_ amount of
     * cc space as there was to begin with.
     */
    line->size += cols - oldcols;
    line->chars = sresize(line->chars, line->size, TTYPE);
    line->cols = cols;

    /*
     * If we're expanding the line, _now_ we move the cc
     * section.
     */
    if (cols > oldcols)
      memmove(line->chars + cols,
              line->chars + oldcols,
              (line->size - line->cols) * TSIZE);

    /*
     * Go through what's left of the original line, and adjust
     * the first cc_next pointer in each list. (All the
     * subsequent ones are still valid because they are
     * relative offsets within the cc block.) Also do the same
     * to the head of the cc_free list.
     */
    for (i = 0; i < oldcols && i < cols; i++)
      if (line->chars[i].cc_next)
        line->chars[i].cc_next += cols - oldcols;
    if (line->cc_free)
      line->cc_free += cols - oldcols;

    /*
     * And finally fill in the new space with erase chars. (We
     * don't have to worry about cc lists here, because we
     * _know_ the erase char doesn't have one.)
     */
    for (i = oldcols; i < cols; i++)
      line->chars[i] = term->basic_erase_char;

#ifdef TERM_CC_DIAGS
    cc_check(line);
#endif
  }
}

/*
 * Get the number of lines in the scrollback.
 */
static int sblines(Terminal *term)
{
  int sblines = count234(term->scrollback);
  if (term->erase_to_scrollback && term->alt_which && term->alt_screen) {
    sblines += term->alt_sblines;
  }
  return sblines;
}

/*
 * Retrieve a line of the screen or of the scrollback, according to
 * whether the y coordinate is non-negative or negative
 * (respectively).
 */
static termline *lineptr(Terminal *term, int y, int lineno, int screen)
{
  termline *line;
  tree234 *whichtree;
  int treeindex;

  if (y >= 0) {
    whichtree = term->screen;
    treeindex = y;
  } else {
    int altlines = 0;

    assert(!screen);

    if (term->erase_to_scrollback && term->alt_which && term->alt_screen) {
      altlines = term->alt_sblines;
    }
    if (y < -altlines) {
      whichtree = term->scrollback;
      treeindex = y + altlines + count234(term->scrollback);
    } else {
      whichtree = term->alt_screen;
      treeindex = y + term->alt_sblines;
      /* treeindex = y + count234(term->alt_screen); */
    }
  }
  if (whichtree == term->scrollback) {
    unsigned char *cline = index234(whichtree, treeindex);
    line = decompressline(cline, NULL);
  } else {
    line = index234(whichtree, treeindex);
  }

  /* We assume that we don't screw up and retrieve something out of range. */
  if (line == NULL) {
    fatalbox("line==NULL in terminal.c\n"
             "lineno=%d y=%d w=%d h=%d\n"
             "count(scrollback=%p)=%d\n"
             "count(screen=%p)=%d\n"
             "count(alt=%p)=%d alt_sblines=%d\n"
             "whichtree=%p treeindex=%d\n\n"
             "Please contact <putty@projects.tartarus.org> "
             "and pass on the above information.",
             lineno,
             y,
             term->cols,
             term->rows,
             term->scrollback,
             count234(term->scrollback),
             term->screen,
             count234(term->screen),
             term->alt_screen,
             count234(term->alt_screen),
             term->alt_sblines,
             whichtree,
             treeindex);
  }
  assert(line != NULL);

  /*
   * Here we resize lines to _at least_ the right length, but we
   * don't truncate them. Truncation is done as a side effect of
   * modifying the line.
   *
   * The point of this policy is to try to arrange that resizing the
   * terminal window repeatedly - e.g. successive steps in an X11
   * opaque window-resize drag, or resizing as a side effect of
   * retiling by tiling WMs such as xmonad - does not throw away
   * data gratuitously. Specifically, we want a sequence of resize
   * operations with no terminal output between them to have the
   * same effect as a single resize to the ultimate terminal size,
   * and also (for the case in which xmonad narrows a window that's
   * scrolling things) we want scrolling up new text at the bottom
   * of a narrowed window to avoid truncating lines further up when
   * the window is re-widened.
   */
  if (term->cols > line->cols)
    resizeline(term, line, term->cols);

  return line;
}

#define lineptr(x) (lineptr)(term, x, __LINE__, FALSE)
#define scrlineptr(x) (lineptr)(term, x, __LINE__, TRUE)

/*
 * Coerce a termline to the terminal's current width. Unlike the
 * optional resize in lineptr() above, this is potentially destructive
 * of text, since it can shrink as well as grow the line.
 *
 * We call this whenever a termline is actually going to be modified.
 * Helpfully, putting a single call to this function in check_boundary
 * deals with _nearly_ all such cases, leaving only a few things like
 * bulk erase and ESC#8 to handle separately.
 */
static void check_line_size(Terminal *term, termline *line)
{
  if (term->cols != line->cols) /* trivial optimisation */
    resizeline(term, line, term->cols);
}

static void term_schedule_tblink(Terminal *term);
static void term_schedule_cblink(Terminal *term);

static void term_timer(void *ctx, unsigned long now)
{
  Terminal *term = (Terminal *)ctx;
  int update = FALSE;

  if (term->tblink_pending && now == term->next_tblink) {
    term->tblinker = !term->tblinker;
    term->tblink_pending = FALSE;
    term_schedule_tblink(term);
    update = TRUE;
  }

  if (term->cblink_pending && now == term->next_cblink) {
    term->cblinker = !term->cblinker;
    term->cblink_pending = FALSE;
    term_schedule_cblink(term);
    update = TRUE;
  }

  if (term->in_vbell && now == term->vbell_end) {
    term->in_vbell = FALSE;
    update = TRUE;
  }

  if (update || (term->window_update_pending && now == term->next_update))
    term_update(term);
}

static void term_schedule_update(Terminal *term)
{
  if (!term->window_update_pending) {
    term->window_update_pending = TRUE;
    term->next_update = schedule_timer(UPDATE_DELAY, term_timer, term);
  }
}

/*
 * Call this whenever the terminal window state changes, to queue
 * an update.
 */
static void seen_disp_event(Terminal *term)
{
  term->seen_disp_event = TRUE; /* for scrollback-reset-on-activity */
  term_schedule_update(term);
}

/*
 * Call when the terminal's blinking-text settings change, or when
 * a text blink has just occurred.
 */
static void term_schedule_tblink(Terminal *term)
{
  if (term->blink_is_real) {
    if (!term->tblink_pending)
      term->next_tblink = schedule_timer(TBLINK_DELAY, term_timer, term);
    term->tblink_pending = TRUE;
  } else {
    term->tblinker = 1; /* reset when not in use */
    term->tblink_pending = FALSE;
  }
}

/*
 * Likewise with cursor blinks.
 */
static void term_schedule_cblink(Terminal *term)
{
  if (term->blink_cur && term->has_focus) {
    if (!term->cblink_pending)
      term->next_cblink = schedule_timer(CBLINK_DELAY, term_timer, term);
    term->cblink_pending = TRUE;
  } else {
    term->cblinker = 1; /* reset when not in use */
    term->cblink_pending = FALSE;
  }
}

/*
 * Call to reset cursor blinking on new output.
 */
static void term_reset_cblink(Terminal *term)
{
  seen_disp_event(term);
  term->cblinker = 1;
  term->cblink_pending = FALSE;
  term_schedule_cblink(term);
}

/*
 * Call to begin a visual bell.
 */
static void term_schedule_vbell(Terminal *term,
                                int already_started,
                                long startpoint)
{
  long ticks_already_gone;

  if (already_started)
    ticks_already_gone = GETTICKCOUNT() - startpoint;
  else
    ticks_already_gone = 0;

  if (ticks_already_gone < VBELL_DELAY) {
    term->in_vbell = TRUE;
    term->vbell_end =
        schedule_timer(VBELL_DELAY - ticks_already_gone, term_timer, term);
  } else {
    term->in_vbell = FALSE;
  }
}

/*
 * Set up power-on settings for the terminal.
 * If 'clear' is false, don't actually clear the primary screen, and
 * position the cursor below the last non-blank line (scrolling if
 * necessary).
 */
static void power_on(Terminal *term, int clear)
{
  term->alt_x = term->alt_y = 0;
  term->savecurs.x = term->savecurs.y = 0;
  term->alt_savecurs.x = term->alt_savecurs.y = 0;
  term->alt_t = term->marg_t = 0;
  if (term->rows != -1)
    term->alt_b = term->marg_b = term->rows - 1;
  else
    term->alt_b = term->marg_b = 0;
  if (term->cols != -1) {
    int i;
    for (i = 0; i < term->cols; i++)
      term->tabs[i] = (i % 8 == 0 ? TRUE : FALSE);
  }
  term->alt_om = term->dec_om = conf_get_int(term->conf, CONF_dec_om);
  term->alt_ins = term->insert = FALSE;
  term->alt_wnext = term->wrapnext = term->save_wnext = term->alt_save_wnext =
      FALSE;
  term->alt_wrap = term->wrap = conf_get_int(term->conf, CONF_wrap_mode);
  term->alt_cset = term->cset = term->save_cset = term->alt_save_cset = 0;
  term->alt_utf = term->utf = term->save_utf = term->alt_save_utf = 0;
  term->utf_state = 0;
  term->alt_sco_acs = term->sco_acs = term->save_sco_acs =
      term->alt_save_sco_acs = 0;
  term->cset_attr[0] = term->cset_attr[1] = term->save_csattr =
      term->alt_save_csattr = CSET_ASCII;
  term->rvideo = 0;
  term->in_vbell = FALSE;
  term->cursor_on = 1;
  term->big_cursor = 0;
  term->default_attr = term->save_attr = term->alt_save_attr = term->curr_attr =
      ATTR_DEFAULT;
  term->term_editing = term->term_echoing = FALSE;
  term->app_cursor_keys = conf_get_int(term->conf, CONF_app_cursor);
  term->app_keypad_keys = conf_get_int(term->conf, CONF_app_keypad);
  term->use_bce = conf_get_int(term->conf, CONF_bce);
  term->blink_is_real = conf_get_int(term->conf, CONF_blinktext);
  term->erase_char = term->basic_erase_char;
  term->alt_which = 0;
  term_print_finish(term);
  term->xterm_mouse = 0;
  term->xterm_extended_mouse = 0;
  term->urxvt_extended_mouse = 0;
  set_raw_mouse_mode(term->frontend, FALSE);
  term->bracketed_paste = FALSE;
  {
    int i;
    for (i = 0; i < 256; i++)
      term->wordness[i] = conf_get_int_int(term->conf, CONF_wordness, i);
  }
  if (term->screen) {
    swap_screen(term, 1, FALSE, FALSE);
    erase_lots(term, FALSE, TRUE, TRUE);
    swap_screen(term, 0, FALSE, FALSE);
    if (clear)
      erase_lots(term, FALSE, TRUE, TRUE);
    term->curs.y = find_last_nonempty_line(term, term->screen) + 1;
    if (term->curs.y == term->rows) {
      term->curs.y--;
      scroll(term, 0, term->rows - 1, 1, TRUE);
    }
  } else {
    term->curs.y = 0;
  }
  term->curs.x = 0;
  term_schedule_tblink(term);
  term_schedule_cblink(term);
}

/*
 * Force a screen update.
 */
void term_update(Terminal *term)
{
  Context ctx;

  term->window_update_pending = FALSE;

  ctx = get_ctx(term->frontend);
  if (ctx) {
    int need_sbar_update = term->seen_disp_event;
    if (term->seen_disp_event && term->scroll_on_disp) {
      term->disptop = 0; /* return to main screen */
      term->seen_disp_event = 0;
      need_sbar_update = TRUE;
    }

    if (need_sbar_update)
      update_sbar(term);
    do_paint(term, ctx, TRUE);
    sys_cursor(term->frontend, term->curs.x, term->curs.y - term->disptop);
    free_ctx(ctx);
  }
}

/*
 * Called from front end when a keypress occurs, to trigger
 * anything magical that needs to happen in that situation.
 */
void term_seen_key_event(Terminal *term)
{
  /*
   * On any keypress, clear the bell overload mechanism
   * completely, on the grounds that large numbers of
   * beeps coming from deliberate key action are likely
   * to be intended (e.g. beeps from filename completion
   * blocking repeatedly).
   */
  term->beep_overloaded = FALSE;
  while (term->beephead) {
    struct beeptime *tmp = term->beephead;
    term->beephead = tmp->next;
    sfree(tmp);
  }
  term->beeptail = NULL;
  term->nbeeps = 0;

  /*
   * Reset the scrollback on keypress, if we're doing that.
   */
  if (term->scroll_on_key) {
    term->disptop = 0; /* return to main screen */
    seen_disp_event(term);
  }
}

/*
 * Same as power_on(), but an external function.
 */
void term_pwron(Terminal *term, int clear)
{
  power_on(term, clear);
  if (term->ldisc) /* cause ldisc to notice changes */
    ldisc_echoedit_update(term->ldisc);
  term->disptop = 0;
  deselect(term);
  term_update(term);
}

static void set_erase_char(Terminal *term)
{
  term->erase_char = term->basic_erase_char;
  if (term->use_bce)
    term->erase_char.attr = (term->curr_attr & (ATTR_FGMASK | ATTR_BGMASK));
}

/*
 * We copy a bunch of stuff out of the Conf structure into local
 * fields in the Terminal structure, to avoid the repeated tree234
 * lookups which would be involved in fetching them from the former
 * every time.
 */
void term_copy_stuff_from_conf(Terminal *term)
{
  term->ansi_colour = conf_get_int(term->conf, CONF_ansi_colour);
  term->arabicshaping = conf_get_int(term->conf, CONF_arabicshaping);
  term->beep = conf_get_int(term->conf, CONF_beep);
  term->bellovl = conf_get_int(term->conf, CONF_bellovl);
  term->bellovl_n = conf_get_int(term->conf, CONF_bellovl_n);
  term->bellovl_s = conf_get_int(term->conf, CONF_bellovl_s);
  term->bellovl_t = conf_get_int(term->conf, CONF_bellovl_t);
  term->bidi = conf_get_int(term->conf, CONF_bidi);
  term->bksp_is_delete = conf_get_int(term->conf, CONF_bksp_is_delete);
  term->blink_cur = conf_get_int(term->conf, CONF_blink_cur);
  term->blinktext = conf_get_int(term->conf, CONF_blinktext);
  term->cjk_ambig_wide = conf_get_int(term->conf, CONF_cjk_ambig_wide);
  term->conf_height = conf_get_int(term->conf, CONF_height);
  term->conf_width = conf_get_int(term->conf, CONF_width);
  term->crhaslf = conf_get_int(term->conf, CONF_crhaslf);
  term->erase_to_scrollback =
      conf_get_int(term->conf, CONF_erase_to_scrollback);
  term->funky_type = conf_get_int(term->conf, CONF_funky_type);
  term->lfhascr = conf_get_int(term->conf, CONF_lfhascr);
  term->logflush = conf_get_int(term->conf, CONF_logflush);
  term->logtype = conf_get_int(term->conf, CONF_logtype);
  term->mouse_override = conf_get_int(term->conf, CONF_mouse_override);
  term->nethack_keypad = conf_get_int(term->conf, CONF_nethack_keypad);
  term->no_alt_screen = conf_get_int(term->conf, CONF_no_alt_screen);
  term->no_applic_c = conf_get_int(term->conf, CONF_no_applic_c);
  term->no_applic_k = conf_get_int(term->conf, CONF_no_applic_k);
  term->no_dbackspace = conf_get_int(term->conf, CONF_no_dbackspace);
  term->no_mouse_rep = conf_get_int(term->conf, CONF_no_mouse_rep);
  term->no_remote_charset = conf_get_int(term->conf, CONF_no_remote_charset);
  term->no_remote_resize = conf_get_int(term->conf, CONF_no_remote_resize);
  term->no_remote_wintitle = conf_get_int(term->conf, CONF_no_remote_wintitle);
  term->no_remote_clearscroll =
      conf_get_int(term->conf, CONF_no_remote_clearscroll);
  term->rawcnp = conf_get_int(term->conf, CONF_rawcnp);
  term->rect_select = conf_get_int(term->conf, CONF_rect_select);
  term->remote_qtitle_action =
      conf_get_int(term->conf, CONF_remote_qtitle_action);
  term->rxvt_homeend = conf_get_int(term->conf, CONF_rxvt_homeend);
  term->scroll_on_disp = conf_get_int(term->conf, CONF_scroll_on_disp);
  term->scroll_on_key = conf_get_int(term->conf, CONF_scroll_on_key);
  term->xterm_256_colour = conf_get_int(term->conf, CONF_xterm_256_colour);

  /*
   * Parse the control-character escapes in the configured
   * answerback string.
   */
  {
    char *answerback = conf_get_str(term->conf, CONF_answerback);
    int maxlen = strlen(answerback);

    term->answerback = snewn(maxlen, char);
    term->answerbacklen = 0;

    while (*answerback) {
      char *n;
      char c = ctrlparse(answerback, &n);
      if (n) {
        term->answerback[term->answerbacklen++] = c;
        answerback = n;
      } else {
        term->answerback[term->answerbacklen++] = *answerback++;
      }
    }
  }
}

/*
 * When the user reconfigures us, we need to check the forbidden-
 * alternate-screen config option, disable raw mouse mode if the
 * user has disabled mouse reporting, and abandon a print job if
 * the user has disabled printing.
 */
void term_reconfig(Terminal *term, Conf *conf)
{
  /*
   * Before adopting the new config, check all those terminal
   * settings which control power-on defaults; and if they've
   * changed, we will modify the current state as well as the
   * default one. The full list is: Auto wrap mode, DEC Origin
   * Mode, BCE, blinking text, character classes.
   */
  int reset_wrap, reset_decom, reset_bce, reset_tblink, reset_charclass;
  int i;

  reset_wrap = (conf_get_int(term->conf, CONF_wrap_mode) !=
                conf_get_int(conf, CONF_wrap_mode));
  reset_decom = (conf_get_int(term->conf, CONF_dec_om) !=
                 conf_get_int(conf, CONF_dec_om));
  reset_bce =
      (conf_get_int(term->conf, CONF_bce) != conf_get_int(conf, CONF_bce));
  reset_tblink = (conf_get_int(term->conf, CONF_blinktext) !=
                  conf_get_int(conf, CONF_blinktext));
  reset_charclass = 0;
  for (i = 0; i < 256; i++)
    if (conf_get_int_int(term->conf, CONF_wordness, i) !=
        conf_get_int_int(conf, CONF_wordness, i))
      reset_charclass = 1;

  /*
   * If the bidi or shaping settings have changed, flush the bidi
   * cache completely.
   */
  if (conf_get_int(term->conf, CONF_arabicshaping) !=
          conf_get_int(conf, CONF_arabicshaping) ||
      conf_get_int(term->conf, CONF_bidi) != conf_get_int(conf, CONF_bidi)) {
    for (i = 0; i < term->bidi_cache_size; i++) {
      sfree(term->pre_bidi_cache[i].chars);
      sfree(term->post_bidi_cache[i].chars);
      term->pre_bidi_cache[i].width = -1;
      term->pre_bidi_cache[i].chars = NULL;
      term->post_bidi_cache[i].width = -1;
      term->post_bidi_cache[i].chars = NULL;
    }
  }

  conf_free(term->conf);
  term->conf = conf_copy(conf);

  if (reset_wrap)
    term->alt_wrap = term->wrap = conf_get_int(term->conf, CONF_wrap_mode);
  if (reset_decom)
    term->alt_om = term->dec_om = conf_get_int(term->conf, CONF_dec_om);
  if (reset_bce) {
    term->use_bce = conf_get_int(term->conf, CONF_bce);
    set_erase_char(term);
  }
  if (reset_tblink) {
    term->blink_is_real = conf_get_int(term->conf, CONF_blinktext);
  }
  if (reset_charclass)
    for (i = 0; i < 256; i++)
      term->wordness[i] = conf_get_int_int(term->conf, CONF_wordness, i);

  if (conf_get_int(term->conf, CONF_no_alt_screen))
    swap_screen(term, 0, FALSE, FALSE);
  if (conf_get_int(term->conf, CONF_no_mouse_rep)) {
    term->xterm_mouse = 0;
    set_raw_mouse_mode(term->frontend, 0);
  }
  if (conf_get_int(term->conf, CONF_no_remote_charset)) {
    term->cset_attr[0] = term->cset_attr[1] = CSET_ASCII;
    term->sco_acs = term->alt_sco_acs = 0;
    term->utf = 0;
  }
  if (!conf_get_str(term->conf, CONF_printer)) {
    term_print_finish(term);
  }
  term_schedule_tblink(term);
  term_schedule_cblink(term);
  term_copy_stuff_from_conf(term);
}

/*
 * Clear the scrollback.
 */
void term_clrsb(Terminal *term)
{
  unsigned char *line;
  int i;

  /*
   * Scroll forward to the current screen, if we were back in the
   * scrollback somewhere until now.
   */
  term->disptop = 0;

  /*
   * Clear the actual scrollback.
   */
  while ((line = delpos234(term->scrollback, 0)) != NULL) {
    sfree(line); /* this is compressed data, not a termline */
  }

  /*
   * When clearing the scrollback, we also truncate any termlines on
   * the current screen which have remembered data from a previous
   * larger window size. Rationale: clearing the scrollback is
   * sometimes done to protect privacy, so the user intention is
   * specifically that we should not retain evidence of what
   * previously happened in the terminal, and that ought to include
   * evidence to the right as well as evidence above.
   */
  for (i = 0; i < term->rows; i++)
    check_line_size(term, scrlineptr(i));

  /*
   * There are now no lines of real scrollback which can be pulled
   * back into the screen by a resize, and no lines of the alternate
   * screen which should be displayed as if part of the scrollback.
   */
  term->tempsblines = 0;
  term->alt_sblines = 0;

  /*
   * Update the scrollbar to reflect the new state of the world.
   */
  update_sbar(term);
}

/*
 * Initialise the terminal.
 */
Terminal *term_init(Conf *myconf, struct unicode_data *ucsdata, void *frontend)
{
  Terminal *term;

  /*
   * Allocate a new Terminal structure and initialise the fields
   * that need it.
   */
  term = snew(Terminal);
  term->frontend = frontend;
  term->ucsdata = ucsdata;
  term->conf = conf_copy(myconf);
  term->logctx = NULL;
  term->compatibility_level = TM_PUTTY;
  strcpy(term->id_string, "\033[?6c");
  term->cblink_pending = term->tblink_pending = FALSE;
  term->paste_buffer = NULL;
  term->paste_len = 0;
  bufchain_init(&term->inbuf);
  bufchain_init(&term->printer_buf);
  term->printing = term->only_printing = FALSE;
  term->print_job = NULL;
  term->vt52_mode = FALSE;
  term->cr_lf_return = FALSE;
  term->seen_disp_event = FALSE;
  term->mouse_is_down = FALSE;
  term->reset_132 = FALSE;
  term->cblinker = term->tblinker = 0;
  term->has_focus = 1;
  term->repeat_off = FALSE;
  term->termstate = TOPLEVEL;
  term->selstate = NO_SELECTION;
  term->curstype = 0;

  term_copy_stuff_from_conf(term);

  term->screen = term->alt_screen = term->scrollback = NULL;
  term->tempsblines = 0;
  term->alt_sblines = 0;
  term->disptop = 0;
  term->disptext = NULL;
  term->dispcursx = term->dispcursy = -1;
  term->tabs = NULL;
  deselect(term);
  term->rows = term->cols = -1;
  power_on(term, TRUE);
  term->beephead = term->beeptail = NULL;
#ifdef OPTIMISE_SCROLL
  term->scrollhead = term->scrolltail = NULL;
#endif /* OPTIMISE_SCROLL */
  term->nbeeps = 0;
  term->lastbeep = FALSE;
  term->beep_overloaded = FALSE;
  term->attr_mask = 0xffffffff;
  term->resize_fn = NULL;
  term->resize_ctx = NULL;
  term->in_term_out = FALSE;
  term->ltemp = NULL;
  term->ltemp_size = 0;
  term->wcFrom = NULL;
  term->wcTo = NULL;
  term->wcFromTo_size = 0;

  term->window_update_pending = FALSE;

  term->bidi_cache_size = 0;
  term->pre_bidi_cache = term->post_bidi_cache = NULL;

  /* FULL-TERMCHAR */
  term->basic_erase_char.chr = CSET_ASCII | ' ';
  term->basic_erase_char.attr = ATTR_DEFAULT;
  term->basic_erase_char.cc_next = 0;
  term->erase_char = term->basic_erase_char;

  // region tray-url
  term->url_update = TRUE;
  // endregion

  return term;
}

void term_free(Terminal *term)
{
  termline *line;
  struct beeptime *beep;
  int i;

  while ((line = delpos234(term->scrollback, 0)) != NULL)
    sfree(line); /* compressed data, not a termline */
  freetree234(term->scrollback);
  while ((line = delpos234(term->screen, 0)) != NULL)
    freeline(line);
  freetree234(term->screen);
  while ((line = delpos234(term->alt_screen, 0)) != NULL)
    freeline(line);
  freetree234(term->alt_screen);
  if (term->disptext) {
    for (i = 0; i < term->rows; i++)
      freeline(term->disptext[i]);
  }
  sfree(term->disptext);
  while (term->beephead) {
    beep = term->beephead;
    term->beephead = beep->next;
    sfree(beep);
  }
  bufchain_clear(&term->inbuf);
  if (term->print_job)
    printer_finish_job(term->print_job);
  bufchain_clear(&term->printer_buf);
  sfree(term->paste_buffer);
  sfree(term->ltemp);
  sfree(term->wcFrom);
  sfree(term->wcTo);

  for (i = 0; i < term->bidi_cache_size; i++) {
    sfree(term->pre_bidi_cache[i].chars);
    sfree(term->post_bidi_cache[i].chars);
    sfree(term->post_bidi_cache[i].forward);
    sfree(term->post_bidi_cache[i].backward);
  }
  sfree(term->pre_bidi_cache);
  sfree(term->post_bidi_cache);

  sfree(term->tabs);

  expire_timer_context(term);

  conf_free(term->conf);

  sfree(term);
}

/*
 * Set up the terminal for a given size.
 */
void term_size(Terminal *term, int newrows, int newcols, int newsavelines)
{
  tree234 *newalt;
  termline **newdisp, *line;
  int i, j, oldrows = term->rows;
  int sblen;
  int save_alt_which = term->alt_which;

  if (newrows == term->rows && newcols == term->cols &&
      newsavelines == term->savelines)
    return; /* nothing to do */

  /* Behave sensibly if we're given zero (or negative) rows/cols */

  if (newrows < 1)
    newrows = 1;
  if (newcols < 1)
    newcols = 1;

  deselect(term);
  swap_screen(term, 0, FALSE, FALSE);

  term->alt_t = term->marg_t = 0;
  term->alt_b = term->marg_b = newrows - 1;

  if (term->rows == -1) {
    term->scrollback = newtree234(NULL);
    term->screen = newtree234(NULL);
    term->tempsblines = 0;
    term->rows = 0;
  }

  /*
   * Resize the screen and scrollback. We only need to shift
   * lines around within our data structures, because lineptr()
   * will take care of resizing each individual line if
   * necessary. So:
   *
   *  - If the new screen is longer, we shunt lines in from temporary
   *    scrollback if possible, otherwise we add new blank lines at
   *    the bottom.
   *
   *  - If the new screen is shorter, we remove any blank lines at
   *    the bottom if possible, otherwise shunt lines above the cursor
   *    to scrollback if possible, otherwise delete lines below the
   *    cursor.
   *
   *  - Then, if the new scrollback length is less than the
   *    amount of scrollback we actually have, we must throw some
   *    away.
   */
  sblen = count234(term->scrollback);
  /* Do this loop to expand the screen if newrows > rows */
  assert(term->rows == count234(term->screen));
  while (term->rows < newrows) {
    if (term->tempsblines > 0) {
      unsigned char *cline;
      /* Insert a line from the scrollback at the top of the screen. */
      assert(sblen >= term->tempsblines);
      cline = delpos234(term->scrollback, --sblen);
      line = decompressline(cline, NULL);
      sfree(cline);
      line->temporary = FALSE; /* reconstituted line is now real */
      term->tempsblines -= 1;
      addpos234(term->screen, line, 0);
      term->curs.y += 1;
      term->savecurs.y += 1;
      term->alt_y += 1;
      term->alt_savecurs.y += 1;
    } else {
      /* Add a new blank line at the bottom of the screen. */
      line = newline(term, newcols, FALSE);
      addpos234(term->screen, line, count234(term->screen));
    }
    term->rows += 1;
  }
  /* Do this loop to shrink the screen if newrows < rows */
  while (term->rows > newrows) {
    if (term->curs.y < term->rows - 1) {
      /* delete bottom row, unless it contains the cursor */
      line = delpos234(term->screen, term->rows - 1);
      freeline(line);
    } else {
      /* push top row to scrollback */
      line = delpos234(term->screen, 0);
      addpos234(term->scrollback, compressline(line), sblen++);
      freeline(line);
      term->tempsblines += 1;
      term->curs.y -= 1;
      term->savecurs.y -= 1;
      term->alt_y -= 1;
      term->alt_savecurs.y -= 1;
    }
    term->rows -= 1;
  }
  assert(term->rows == newrows);
  assert(count234(term->screen) == newrows);

  /* Delete any excess lines from the scrollback. */
  while (sblen > newsavelines) {
    line = delpos234(term->scrollback, 0);
    sfree(line);
    sblen--;
  }
  if (sblen < term->tempsblines)
    term->tempsblines = sblen;
  assert(count234(term->scrollback) <= newsavelines);
  assert(count234(term->scrollback) >= term->tempsblines);
  term->disptop = 0;

  /* Make a new displayed text buffer. */
  newdisp = snewn(newrows, termline *);
  for (i = 0; i < newrows; i++) {
    newdisp[i] = newline(term, newcols, FALSE);
    for (j = 0; j < newcols; j++)
      newdisp[i]->chars[j].attr = ATTR_INVALID;
  }
  if (term->disptext) {
    for (i = 0; i < oldrows; i++)
      freeline(term->disptext[i]);
  }
  sfree(term->disptext);
  term->disptext = newdisp;
  term->dispcursx = term->dispcursy = -1;

  /* Make a new alternate screen. */
  newalt = newtree234(NULL);
  for (i = 0; i < newrows; i++) {
    line = newline(term, newcols, TRUE);
    addpos234(newalt, line, i);
  }
  if (term->alt_screen) {
    while (NULL != (line = delpos234(term->alt_screen, 0)))
      freeline(line);
    freetree234(term->alt_screen);
  }
  term->alt_screen = newalt;
  term->alt_sblines = 0;

  term->tabs = sresize(term->tabs, newcols, unsigned char);
  {
    int i;
    for (i = (term->cols > 0 ? term->cols : 0); i < newcols; i++)
      term->tabs[i] = (i % 8 == 0 ? TRUE : FALSE);
  }

  /* Check that the cursor positions are still valid. */
  if (term->savecurs.y < 0)
    term->savecurs.y = 0;
  if (term->savecurs.y >= newrows)
    term->savecurs.y = newrows - 1;
  if (term->savecurs.x >= newcols)
    term->savecurs.x = newcols - 1;
  if (term->alt_savecurs.y < 0)
    term->alt_savecurs.y = 0;
  if (term->alt_savecurs.y >= newrows)
    term->alt_savecurs.y = newrows - 1;
  if (term->alt_savecurs.x >= newcols)
    term->alt_savecurs.x = newcols - 1;
  if (term->curs.y < 0)
    term->curs.y = 0;
  if (term->curs.y >= newrows)
    term->curs.y = newrows - 1;
  if (term->curs.x >= newcols)
    term->curs.x = newcols - 1;
  if (term->alt_y < 0)
    term->alt_y = 0;
  if (term->alt_y >= newrows)
    term->alt_y = newrows - 1;
  if (term->alt_x >= newcols)
    term->alt_x = newcols - 1;
  term->alt_x = term->alt_y = 0;
  term->wrapnext = term->alt_wnext = FALSE;

  term->rows = newrows;
  term->cols = newcols;
  term->savelines = newsavelines;

  swap_screen(term, save_alt_which, FALSE, FALSE);

  update_sbar(term);
  term_update(term);
  if (term->resize_fn)
    term->resize_fn(term->resize_ctx, term->cols, term->rows);
}

/*
 * Hand a function and context pointer to the terminal which it can
 * use to notify a back end of resizes.
 */
void term_provide_resize_fn(Terminal *term,
                            void (*resize_fn)(void *, int, int),
                            void *resize_ctx)
{
  term->resize_fn = resize_fn;
  term->resize_ctx = resize_ctx;
  if (resize_fn && term->cols > 0 && term->rows > 0)
    resize_fn(resize_ctx, term->cols, term->rows);
}

/* Find the bottom line on the screen that has any content.
 * If only the top line has content, returns 0.
 * If no lines have content, return -1.
 */
static int find_last_nonempty_line(Terminal *term, tree234 *screen)
{
  int i;
  for (i = count234(screen) - 1; i >= 0; i--) {
    termline *line = index234(screen, i);
    int j;
    for (j = 0; j < line->cols; j++)
      if (!termchars_equal(&line->chars[j], &term->erase_char))
        break;
    if (j != line->cols)
      break;
  }
  return i;
}

/*
 * Swap screens. If `reset' is TRUE and we have been asked to
 * switch to the alternate screen, we must bring most of its
 * configuration from the main screen and erase the contents of the
 * alternate screen completely. (This is even true if we're already
 * on it! Blame xterm.)
 */
static void swap_screen(Terminal *term, int which, int reset, int keep_cur_pos)
{
  int t;
  pos tp;
  tree234 *ttr;

  if (!which)
    reset = FALSE; /* do no weird resetting if which==0 */

  if (which != term->alt_which) {
    term->alt_which = which;

    ttr = term->alt_screen;
    term->alt_screen = term->screen;
    term->screen = ttr;
    term->alt_sblines = find_last_nonempty_line(term, term->alt_screen) + 1;
    t = term->curs.x;
    if (!reset && !keep_cur_pos)
      term->curs.x = term->alt_x;
    term->alt_x = t;
    t = term->curs.y;
    if (!reset && !keep_cur_pos)
      term->curs.y = term->alt_y;
    term->alt_y = t;
    t = term->marg_t;
    if (!reset)
      term->marg_t = term->alt_t;
    term->alt_t = t;
    t = term->marg_b;
    if (!reset)
      term->marg_b = term->alt_b;
    term->alt_b = t;
    t = term->dec_om;
    if (!reset)
      term->dec_om = term->alt_om;
    term->alt_om = t;
    t = term->wrap;
    if (!reset)
      term->wrap = term->alt_wrap;
    term->alt_wrap = t;
    t = term->wrapnext;
    if (!reset)
      term->wrapnext = term->alt_wnext;
    term->alt_wnext = t;
    t = term->insert;
    if (!reset)
      term->insert = term->alt_ins;
    term->alt_ins = t;
    t = term->cset;
    if (!reset)
      term->cset = term->alt_cset;
    term->alt_cset = t;
    t = term->utf;
    if (!reset)
      term->utf = term->alt_utf;
    term->alt_utf = t;
    t = term->sco_acs;
    if (!reset)
      term->sco_acs = term->alt_sco_acs;
    term->alt_sco_acs = t;

    tp = term->savecurs;
    if (!reset && !keep_cur_pos)
      term->savecurs = term->alt_savecurs;
    term->alt_savecurs = tp;
    t = term->save_cset;
    if (!reset && !keep_cur_pos)
      term->save_cset = term->alt_save_cset;
    term->alt_save_cset = t;
    t = term->save_csattr;
    if (!reset && !keep_cur_pos)
      term->save_csattr = term->alt_save_csattr;
    term->alt_save_csattr = t;
    t = term->save_attr;
    if (!reset && !keep_cur_pos)
      term->save_attr = term->alt_save_attr;
    term->alt_save_attr = t;
    t = term->save_utf;
    if (!reset && !keep_cur_pos)
      term->save_utf = term->alt_save_utf;
    term->alt_save_utf = t;
    t = term->save_wnext;
    if (!reset && !keep_cur_pos)
      term->save_wnext = term->alt_save_wnext;
    term->alt_save_wnext = t;
    t = term->save_sco_acs;
    if (!reset && !keep_cur_pos)
      term->save_sco_acs = term->alt_save_sco_acs;
    term->alt_save_sco_acs = t;
  }

  if (reset && term->screen) {
    /*
     * Yes, this _is_ supposed to honour background-colour-erase.
     */
    erase_lots(term, FALSE, TRUE, TRUE);
  }
}

/*
 * Update the scroll bar.
 */
static void update_sbar(Terminal *term)
{
  int nscroll = sblines(term);
  set_sbar(term->frontend,
           nscroll + term->rows,
           nscroll + term->disptop,
           term->rows);
}

/*
 * Check whether the region bounded by the two pointers intersects
 * the scroll region, and de-select the on-screen selection if so.
 */
static void check_selection(Terminal *term, pos from, pos to)
{
  if (poslt(from, term->selend) && poslt(term->selstart, to))
    deselect(term);
}

/*
 * Scroll the screen. (`lines' is +ve for scrolling forward, -ve
 * for backward.) `sb' is TRUE if the scrolling is permitted to
 * affect the scrollback buffer.
 */
static void scroll(Terminal *term, int topline, int botline, int lines, int sb)
{
  termline *line;
  int i, seltop, scrollwinsize;
#ifdef OPTIMISE_SCROLL
  int olddisptop, shift;
#endif /* OPTIMISE_SCROLL */

  if (topline != 0 || term->alt_which != 0)
    sb = FALSE;

#ifdef OPTIMISE_SCROLL
  olddisptop = term->disptop;
  shift = lines;
#endif /* OPTIMISE_SCROLL */

  scrollwinsize = botline - topline + 1;

  if (lines < 0) {
    lines = -lines;
    if (lines > scrollwinsize)
      lines = scrollwinsize;
    while (lines-- > 0) {
      line = delpos234(term->screen, botline);
      resizeline(term, line, term->cols);
      for (i = 0; i < term->cols; i++)
        copy_termchar(line, i, &term->erase_char);
      line->lattr = LATTR_NORM;
      addpos234(term->screen, line, topline);

      if (term->selstart.y >= topline && term->selstart.y <= botline) {
        term->selstart.y++;
        if (term->selstart.y > botline) {
          term->selstart.y = botline + 1;
          term->selstart.x = 0;
        }
      }
      if (term->selend.y >= topline && term->selend.y <= botline) {
        term->selend.y++;
        if (term->selend.y > botline) {
          term->selend.y = botline + 1;
          term->selend.x = 0;
        }
      }
    }
  } else {
    if (lines > scrollwinsize)
      lines = scrollwinsize;
    while (lines-- > 0) {
      line = delpos234(term->screen, topline);
#ifdef TERM_CC_DIAGS
      cc_check(line);
#endif
      if (sb && term->savelines > 0) {
        int sblen = count234(term->scrollback);
        /*
         * We must add this line to the scrollback. We'll
         * remove a line from the top of the scrollback if
         * the scrollback is full.
         */
        if (sblen == term->savelines) {
          unsigned char *cline;

          sblen--;
          cline = delpos234(term->scrollback, 0);
          sfree(cline);
        } else
          term->tempsblines += 1;

        addpos234(term->scrollback, compressline(line), sblen);

        /* now `line' itself can be reused as the bottom line */

        /*
         * If the user is currently looking at part of the
         * scrollback, and they haven't enabled any options
         * that are going to reset the scrollback as a
         * result of this movement, then the chances are
         * they'd like to keep looking at the same line. So
         * we move their viewpoint at the same rate as the
         * scroll, at least until their viewpoint hits the
         * top end of the scrollback buffer, at which point
         * we don't have the choice any more.
         *
         * Thanks to Jan Holmen Holsten for the idea and
         * initial implementation.
         */
        if (term->disptop > -term->savelines && term->disptop < 0)
          term->disptop--;
      }
      resizeline(term, line, term->cols);
      for (i = 0; i < term->cols; i++)
        copy_termchar(line, i, &term->erase_char);
      line->lattr = LATTR_NORM;
      addpos234(term->screen, line, botline);

      /*
       * If the selection endpoints move into the scrollback,
       * we keep them moving until they hit the top. However,
       * of course, if the line _hasn't_ moved into the
       * scrollback then we don't do this, and cut them off
       * at the top of the scroll region.
       *
       * This applies to selstart and selend (for an existing
       * selection), and also selanchor (for one being
       * selected as we speak).
       */
      seltop = sb ? -term->savelines : topline;

      if (term->selstate != NO_SELECTION) {
        if (term->selstart.y >= seltop && term->selstart.y <= botline) {
          term->selstart.y--;
          if (term->selstart.y < seltop) {
            term->selstart.y = seltop;
            term->selstart.x = 0;
          }
        }
        if (term->selend.y >= seltop && term->selend.y <= botline) {
          term->selend.y--;
          if (term->selend.y < seltop) {
            term->selend.y = seltop;
            term->selend.x = 0;
          }
        }
        if (term->selanchor.y >= seltop && term->selanchor.y <= botline) {
          term->selanchor.y--;
          if (term->selanchor.y < seltop) {
            term->selanchor.y = seltop;
            term->selanchor.x = 0;
          }
        }
      }
    }
  }
#ifdef OPTIMISE_SCROLL
  shift += term->disptop - olddisptop;
  if (shift < term->rows && shift > -term->rows && shift != 0)
    scroll_display(term, topline, botline, shift);
#endif /* OPTIMISE_SCROLL */
}

#ifdef OPTIMISE_SCROLL
/*
 * Add a scroll of a region on the screen into the pending scroll list.
 * `lines' is +ve for scrolling forward, -ve for backward.
 *
 * If the scroll is on the same area as the last scroll in the list,
 * merge them.
 */
static void save_scroll(Terminal *term, int topline, int botline, int lines)
{
  struct scrollregion *newscroll;
  if (term->scrolltail && term->scrolltail->topline == topline &&
      term->scrolltail->botline == botline) {
    term->scrolltail->lines += lines;
  } else {
    newscroll = snew(struct scrollregion);
    newscroll->topline = topline;
    newscroll->botline = botline;
    newscroll->lines = lines;
    newscroll->next = NULL;

    if (!term->scrollhead)
      term->scrollhead = newscroll;
    else
      term->scrolltail->next = newscroll;
    term->scrolltail = newscroll;
  }
}

/*
 * Scroll the physical display, and our conception of it in disptext.
 */
static void scroll_display(Terminal *term, int topline, int botline, int lines)
{
  int distance, nlines, i, j;

  distance = lines > 0 ? lines : -lines;
  nlines = botline - topline + 1 - distance;
  if (lines > 0) {
    for (i = 0; i < nlines; i++)
      for (j = 0; j < term->cols; j++)
        copy_termchar(
            term->disptext[i], j, term->disptext[i + distance]->chars + j);
    if (term->dispcursy >= 0 && term->dispcursy >= topline + distance &&
        term->dispcursy < topline + distance + nlines)
      term->dispcursy -= distance;
    for (i = 0; i < distance; i++)
      for (j = 0; j < term->cols; j++)
        term->disptext[nlines + i]->chars[j].attr |= ATTR_INVALID;
  } else {
    for (i = nlines; i--;)
      for (j = 0; j < term->cols; j++)
        copy_termchar(
            term->disptext[i + distance], j, term->disptext[i]->chars + j);
    if (term->dispcursy >= 0 && term->dispcursy >= topline &&
        term->dispcursy < topline + nlines)
      term->dispcursy += distance;
    for (i = 0; i < distance; i++)
      for (j = 0; j < term->cols; j++)
        term->disptext[i]->chars[j].attr |= ATTR_INVALID;
  }
  save_scroll(term, topline, botline, lines);
}
#endif /* OPTIMISE_SCROLL */

/*
 * Move the cursor to a given position, clipping at boundaries. We
 * may or may not want to clip at the scroll margin: marg_clip is 0
 * not to, 1 to disallow _passing_ the margins, and 2 to disallow
 * even _being_ outside the margins.
 */
static void move(Terminal *term, int x, int y, int marg_clip)
{
  if (x < 0)
    x = 0;
  if (x >= term->cols)
    x = term->cols - 1;
  if (marg_clip) {
    if ((term->curs.y >= term->marg_t || marg_clip == 2) && y < term->marg_t)
      y = term->marg_t;
    if ((term->curs.y <= term->marg_b || marg_clip == 2) && y > term->marg_b)
      y = term->marg_b;
  }
  if (y < 0)
    y = 0;
  if (y >= term->rows)
    y = term->rows - 1;
  term->curs.x = x;
  term->curs.y = y;
  term->wrapnext = FALSE;
}

/*
 * Save or restore the cursor and SGR mode.
 */
static void save_cursor(Terminal *term, int save)
{
  if (save) {
    term->savecurs = term->curs;
    term->save_attr = term->curr_attr;
    term->save_cset = term->cset;
    term->save_utf = term->utf;
    term->save_wnext = term->wrapnext;
    term->save_csattr = term->cset_attr[term->cset];
    term->save_sco_acs = term->sco_acs;
  } else {
    term->curs = term->savecurs;
    /* Make sure the window hasn't shrunk since the save */
    if (term->curs.x >= term->cols)
      term->curs.x = term->cols - 1;
    if (term->curs.y >= term->rows)
      term->curs.y = term->rows - 1;

    term->curr_attr = term->save_attr;
    term->cset = term->save_cset;
    term->utf = term->save_utf;
    term->wrapnext = term->save_wnext;
    /*
     * wrapnext might reset to False if the x position is no
     * longer at the rightmost edge.
     */
    if (term->wrapnext && term->curs.x < term->cols - 1)
      term->wrapnext = FALSE;
    term->cset_attr[term->cset] = term->save_csattr;
    term->sco_acs = term->save_sco_acs;
    set_erase_char(term);
  }
}

/*
 * This function is called before doing _anything_ which affects
 * only part of a line of text. It is used to mark the boundary
 * between two character positions, and it indicates that some sort
 * of effect is going to happen on only one side of that boundary.
 *
 * The effect of this function is to check whether a CJK
 * double-width character is straddling the boundary, and to remove
 * it and replace it with two spaces if so. (Of course, one or
 * other of those spaces is then likely to be replaced with
 * something else again, as a result of whatever happens next.)
 *
 * Also, if the boundary is at the right-hand _edge_ of the screen,
 * it implies something deliberate is being done to the rightmost
 * column position; hence we must clear LATTR_WRAPPED2.
 *
 * The input to the function is the coordinates of the _second_
 * character of the pair.
 */
static void check_boundary(Terminal *term, int x, int y)
{
  termline *ldata;

  /* Validate input coordinates, just in case. */
  if (x <= 0 || x > term->cols)
    return;

  ldata = scrlineptr(y);
  check_line_size(term, ldata);
  if (x == term->cols) {
    ldata->lattr &= ~LATTR_WRAPPED2;
  } else {
    if (ldata->chars[x].chr == UCSWIDE) {
      clear_cc(ldata, x - 1);
      clear_cc(ldata, x);
      ldata->chars[x - 1].chr = ' ' | CSET_ASCII;
      ldata->chars[x] = ldata->chars[x - 1];
    }
  }
}

/*
 * Erase a large portion of the screen: the whole screen, or the
 * whole line, or parts thereof.
 */
static void erase_lots(Terminal *term,
                       int line_only,
                       int from_begin,
                       int to_end)
{
  pos start, end;
  int erase_lattr;
  int erasing_lines_from_top = 0;

  if (line_only) {
    start.y = term->curs.y;
    start.x = 0;
    end.y = term->curs.y + 1;
    end.x = 0;
    erase_lattr = FALSE;
  } else {
    start.y = 0;
    start.x = 0;
    end.y = term->rows;
    end.x = 0;
    erase_lattr = TRUE;
  }
  if (!from_begin) {
    start = term->curs;
  }
  if (!to_end) {
    end = term->curs;
    incpos(end);
  }
  if (!from_begin || !to_end)
    check_boundary(term, term->curs.x, term->curs.y);
  check_selection(term, start, end);

  /* Clear screen also forces a full window redraw, just in case. */
  if (start.y == 0 && start.x == 0 && end.y == term->rows)
    term_invalidate(term);

  /* Lines scrolled away shouldn't be brought back on if the terminal
   * resizes. */
  if (start.y == 0 && start.x == 0 && end.x == 0 && erase_lattr)
    erasing_lines_from_top = 1;

  if (term->erase_to_scrollback && erasing_lines_from_top) {
    /* If it's a whole number of lines, starting at the top, and
     * we're fully erasing them, erase by scrolling and keep the
     * lines in the scrollback. */
    int scrolllines = end.y;
    if (end.y == term->rows) {
      /* Shrink until we find a non-empty row.*/
      scrolllines = find_last_nonempty_line(term, term->screen) + 1;
    }
    if (scrolllines > 0)
      scroll(term, 0, scrolllines - 1, scrolllines, TRUE);
  } else {
    termline *ldata = scrlineptr(start.y);
    while (poslt(start, end)) {
      check_line_size(term, ldata);
      if (start.x == term->cols) {
        if (!erase_lattr)
          ldata->lattr &= ~(LATTR_WRAPPED | LATTR_WRAPPED2);
        else
          ldata->lattr = LATTR_NORM;
      } else {
        copy_termchar(ldata, start.x, &term->erase_char);
      }
      if (incpos(start) && start.y < term->rows) {
        ldata = scrlineptr(start.y);
      }
    }
  }

  /* After an erase of lines from the top of the screen, we shouldn't
   * bring the lines back again if the terminal enlarges (since the user or
   * application has explicitly thrown them away). */
  if (erasing_lines_from_top && !(term->alt_which))
    term->tempsblines = 0;
}

/*
 * Insert or delete characters within the current line. n is +ve if
 * insertion is desired, and -ve for deletion.
 */
static void insch(Terminal *term, int n)
{
  int dir = (n < 0 ? -1 : +1);
  int m, j;
  pos eol;
  termline *ldata;

  n = (n < 0 ? -n : n);
  if (n > term->cols - term->curs.x)
    n = term->cols - term->curs.x;
  m = term->cols - term->curs.x - n;

  /*
   * We must de-highlight the selection if it overlaps any part of
   * the region affected by this operation, i.e. the region from the
   * current cursor position to end-of-line, _unless_ the entirety
   * of the selection is going to be moved to the left or right by
   * this operation but otherwise unchanged, in which case we can
   * simply move the highlight with the text.
   */
  eol.y = term->curs.y;
  eol.x = term->cols;
  if (poslt(term->curs, term->selend) && poslt(term->selstart, eol)) {
    pos okstart = term->curs;
    pos okend = eol;
    if (dir > 0) {
      /* Insertion: n characters at EOL will be splatted. */
      okend.x -= n;
    } else {
      /* Deletion: n characters at cursor position will be splatted. */
      okstart.x += n;
    }
    if (posle(okstart, term->selstart) && posle(term->selend, okend)) {
      /* Selection is contained entirely in the interval
       * [okstart,okend), so we need only adjust the selection
       * bounds. */
      term->selstart.x += dir * n;
      term->selend.x += dir * n;
      assert(term->selstart.x >= term->curs.x);
      assert(term->selstart.x < term->cols);
      assert(term->selend.x > term->curs.x);
      assert(term->selend.x <= term->cols);
    } else {
      /* Selection is not wholly contained in that interval, so
       * we must unhighlight it. */
      deselect(term);
    }
  }

  check_boundary(term, term->curs.x, term->curs.y);
  if (dir < 0)
    check_boundary(term, term->curs.x + n, term->curs.y);
  ldata = scrlineptr(term->curs.y);
  if (dir < 0) {
    for (j = 0; j < m; j++)
      move_termchar(ldata,
                    ldata->chars + term->curs.x + j,
                    ldata->chars + term->curs.x + j + n);
    while (n--)
      copy_termchar(ldata, term->curs.x + m++, &term->erase_char);
  } else {
    for (j = m; j--;)
      move_termchar(ldata,
                    ldata->chars + term->curs.x + j + n,
                    ldata->chars + term->curs.x + j);
    while (n--)
      copy_termchar(ldata, term->curs.x + n, &term->erase_char);
  }
}

/*
 * Toggle terminal mode `mode' to state `state'. (`query' indicates
 * whether the mode is a DEC private one or a normal one.)
 */
static void toggle_mode(Terminal *term, int mode, int query, int state)
{
  if (query)
    switch (mode) {
    case 1: /* DECCKM: application cursor keys */
      term->app_cursor_keys = state;
      break;
    case 2: /* DECANM: VT52 mode */
      term->vt52_mode = !state;
      if (term->vt52_mode) {
        term->blink_is_real = FALSE;
        term->vt52_bold = FALSE;
      } else {
        term->blink_is_real = term->blinktext;
      }
      term_schedule_tblink(term);
      break;
    case 3: /* DECCOLM: 80/132 columns */
      deselect(term);
      if (!term->no_remote_resize)
        request_resize(term->frontend, state ? 132 : 80, term->rows);
      term->reset_132 = state;
      term->alt_t = term->marg_t = 0;
      term->alt_b = term->marg_b = term->rows - 1;
      move(term, 0, 0, 0);
      erase_lots(term, FALSE, TRUE, TRUE);
      break;
    case 5: /* DECSCNM: reverse video */
      /*
       * Toggle reverse video. If we receive an OFF within the
       * visual bell timeout period after an ON, we trigger an
       * effective visual bell, so that ESC[?5hESC[?5l will
       * always be an actually _visible_ visual bell.
       */
      if (term->rvideo && !state) {
        /* This is an OFF, so set up a vbell */
        term_schedule_vbell(term, TRUE, term->rvbell_startpoint);
      } else if (!term->rvideo && state) {
        /* This is an ON, so we notice the time and save it. */
        term->rvbell_startpoint = GETTICKCOUNT();
      }
      term->rvideo = state;
      seen_disp_event(term);
      break;
    case 6: /* DECOM: DEC origin mode */
      term->dec_om = state;
      break;
    case 7: /* DECAWM: auto wrap */
      term->wrap = state;
      break;
    case 8: /* DECARM: auto key repeat */
      term->repeat_off = !state;
      break;
    case 10: /* DECEDM: set local edit mode */
      term->term_editing = state;
      if (term->ldisc) /* cause ldisc to notice changes */
        ldisc_echoedit_update(term->ldisc);
      break;
    case 25: /* DECTCEM: enable/disable cursor */
      compatibility2(OTHER, VT220);
      term->cursor_on = state;
      seen_disp_event(term);
      break;
    case 47: /* alternate screen */
      compatibility(OTHER);
      deselect(term);
      swap_screen(term, term->no_alt_screen ? 0 : state, FALSE, FALSE);
      if (term->scroll_on_disp)
        term->disptop = 0;
      break;
    case 1000: /* xterm mouse 1 (normal) */
      term->xterm_mouse = state ? 1 : 0;
      set_raw_mouse_mode(term->frontend, state);
      break;
    case 1002: /* xterm mouse 2 (inc. button drags) */
      term->xterm_mouse = state ? 2 : 0;
      set_raw_mouse_mode(term->frontend, state);
      break;
    case 1006: /* xterm extended mouse */
      term->xterm_extended_mouse = state ? 1 : 0;
      break;
    case 1015: /* urxvt extended mouse */
      term->urxvt_extended_mouse = state ? 1 : 0;
      break;
    case 1047: /* alternate screen */
      compatibility(OTHER);
      deselect(term);
      swap_screen(term, term->no_alt_screen ? 0 : state, TRUE, TRUE);
      if (term->scroll_on_disp)
        term->disptop = 0;
      break;
    case 1048: /* save/restore cursor */
      if (!term->no_alt_screen)
        save_cursor(term, state);
      if (!state)
        seen_disp_event(term);
      break;
    case 1049: /* cursor & alternate screen */
      if (state && !term->no_alt_screen)
        save_cursor(term, state);
      if (!state)
        seen_disp_event(term);
      compatibility(OTHER);
      deselect(term);
      swap_screen(term, term->no_alt_screen ? 0 : state, TRUE, FALSE);
      if (!state && !term->no_alt_screen)
        save_cursor(term, state);
      if (term->scroll_on_disp)
        term->disptop = 0;
      break;
    case 2004: /* xterm bracketed paste */
      term->bracketed_paste = state ? TRUE : FALSE;
      break;
    }
  else
    switch (mode) {
    case 4: /* IRM: set insert mode */
      compatibility(VT102);
      term->insert = state;
      break;
    case 12: /* SRM: set echo mode */
      term->term_echoing = !state;
      if (term->ldisc) /* cause ldisc to notice changes */
        ldisc_echoedit_update(term->ldisc);
      break;
    case 20: /* LNM: Return sends ... */
      term->cr_lf_return = state;
      break;
    case 34: /* WYULCURM: Make cursor BIG */
      compatibility2(OTHER, VT220);
      term->big_cursor = !state;
    }
}

/*
 * Process an OSC sequence: set window title or icon name.
 */
static void do_osc(Terminal *term)
{
  if (term->osc_w) {
    while (term->osc_strlen--)
      term->wordness[(unsigned char)term->osc_string[term->osc_strlen]] =
          term->esc_args[0];
  } else {
    term->osc_string[term->osc_strlen] = '\0';
    switch (term->esc_args[0]) {
    case 0:
    case 1:
      if (!term->no_remote_wintitle)
        set_icon(term->frontend, term->osc_string);
      if (term->esc_args[0] == 1)
        break;
      /* fall through: parameter 0 means set both */
    case 2:
    case 21:
      if (!term->no_remote_wintitle)
        set_title(term->frontend, term->osc_string);
      break;
    }
  }
}

/*
 * ANSI printing routines.
 */
static void term_print_setup(Terminal *term, char *printer)
{
  bufchain_clear(&term->printer_buf);
  term->print_job = printer_start_job(printer);
}
static void term_print_flush(Terminal *term)
{
  void *data;
  int len;
  int size;
  while ((size = bufchain_size(&term->printer_buf)) > 5) {
    bufchain_prefix(&term->printer_buf, &data, &len);
    if (len > size - 5)
      len = size - 5;
    printer_job_data(term->print_job, data, len);
    bufchain_consume(&term->printer_buf, len);
  }
}
static void term_print_finish(Terminal *term)
{
  void *data;
  int len, size;
  char c;

  if (!term->printing && !term->only_printing)
    return; /* we need do nothing */

  term_print_flush(term);
  while ((size = bufchain_size(&term->printer_buf)) > 0) {
    bufchain_prefix(&term->printer_buf, &data, &len);
    c = *(char *)data;
    if (c == '\033' || c == '\233') {
      bufchain_consume(&term->printer_buf, size);
      break;
    } else {
      printer_job_data(term->print_job, &c, 1);
      bufchain_consume(&term->printer_buf, 1);
    }
  }
  printer_finish_job(term->print_job);
  term->print_job = NULL;
  term->printing = term->only_printing = FALSE;
}

/*
 * Remove everything currently in `inbuf' and stick it up on the
 * in-memory display. There's a big state machine in here to
 * process escape sequences...
 */
static void term_out(Terminal *term)
{
  unsigned long c;
  int unget;
  unsigned char localbuf[256], *chars;
  int nchars = 0;

  unget = -1;

  chars = NULL; /* placate compiler warnings */
  while (nchars > 0 || unget != -1 || bufchain_size(&term->inbuf) > 0) {
    if (unget == -1) {
      if (nchars == 0) {
        void *ret;
        bufchain_prefix(&term->inbuf, &ret, &nchars);
        if (nchars > sizeof(localbuf))
          nchars = sizeof(localbuf);
        memcpy(localbuf, ret, nchars);
        bufchain_consume(&term->inbuf, nchars);
        chars = localbuf;
        assert(chars != NULL);
      }
      c = *chars++;
      nchars--;

      /*
       * Optionally log the session traffic to a file. Useful for
       * debugging and possibly also useful for actual logging.
       */
      if (term->logtype == LGTYP_DEBUG && term->logctx)
        logtraffic(term->logctx, (unsigned char)c, LGTYP_DEBUG);
    } else {
      c = unget;
      unget = -1;
    }

    /* Note only VT220+ are 8-bit VT102 is seven bit, it shouldn't even
     * be able to display 8-bit characters, but I'll let that go 'cause
     * of i18n.
     */

    /*
     * If we're printing, add the character to the printer
     * buffer.
     */
    if (term->printing) {
      bufchain_add(&term->printer_buf, &c, 1);

      /*
       * If we're in print-only mode, we use a much simpler
       * state machine designed only to recognise the ESC[4i
       * termination sequence.
       */
      if (term->only_printing) {
        if (c == '\033')
          term->print_state = 1;
        else if (c == (unsigned char)'\233')
          term->print_state = 2;
        else if (c == '[' && term->print_state == 1)
          term->print_state = 2;
        else if (c == '4' && term->print_state == 2)
          term->print_state = 3;
        else if (c == 'i' && term->print_state == 3)
          term->print_state = 4;
        else
          term->print_state = 0;
        if (term->print_state == 4) {
          term_print_finish(term);
        }
        continue;
      }
    }

    /* First see about all those translations. */
    if (term->termstate == TOPLEVEL) {
      if (in_utf(term))
        switch (term->utf_state) {
        case 0:
          if (c < 0x80) {
            /* UTF-8 must be stateless so we ignore iso2022. */
            if (term->ucsdata->unitab_ctrl[c] != 0xFF)
              c = term->ucsdata->unitab_ctrl[c];
            else
              c = ((unsigned char)c) | CSET_ASCII;
            break;
          } else if ((c & 0xe0) == 0xc0) {
            term->utf_size = term->utf_state = 1;
            term->utf_char = (c & 0x1f);
          } else if ((c & 0xf0) == 0xe0) {
            term->utf_size = term->utf_state = 2;
            term->utf_char = (c & 0x0f);
          } else if ((c & 0xf8) == 0xf0) {
            term->utf_size = term->utf_state = 3;
            term->utf_char = (c & 0x07);
          } else if ((c & 0xfc) == 0xf8) {
            term->utf_size = term->utf_state = 4;
            term->utf_char = (c & 0x03);
          } else if ((c & 0xfe) == 0xfc) {
            term->utf_size = term->utf_state = 5;
            term->utf_char = (c & 0x01);
          } else {
            c = UCSERR;
            break;
          }
          continue;
        case 1:
        case 2:
        case 3:
        case 4:
        case 5:
          if ((c & 0xC0) != 0x80) {
            unget = c;
            c = UCSERR;
            term->utf_state = 0;
            break;
          }
          term->utf_char = (term->utf_char << 6) | (c & 0x3f);
          if (--term->utf_state)
            continue;

          c = term->utf_char;

          /* Is somebody trying to be evil! */
          if (c < 0x80 || (c < 0x800 && term->utf_size >= 2) ||
              (c < 0x10000 && term->utf_size >= 3) ||
              (c < 0x200000 && term->utf_size >= 4) ||
              (c < 0x4000000 && term->utf_size >= 5))
            c = UCSERR;

          /* Unicode line separator and paragraph separator are CR-LF */
          if (c == 0x2028 || c == 0x2029)
            c = 0x85;

          /* High controls are probably a Baaad idea too. */
          if (c < 0xA0)
            c = 0xFFFD;

          /* The UTF-16 surrogates are not nice either. */
          /*       The standard give the option of decoding these:
           *       I don't want to! */
          if (c >= 0xD800 && c < 0xE000)
            c = UCSERR;

          /* ISO 10646 characters now limited to UTF-16 range. */
          if (c > 0x10FFFF)
            c = UCSERR;

          /* This is currently a TagPhobic application.. */
          if (c >= 0xE0000 && c <= 0xE007F)
            continue;

          /* U+FEFF is best seen as a null. */
          if (c == 0xFEFF)
            continue;
          /* But U+FFFE is an error. */
          if (c == 0xFFFE || c == 0xFFFF)
            c = UCSERR;

          break;
        }
      /* Are we in the nasty ACS mode? Note: no sco in utf mode. */
      else if (term->sco_acs &&
               (c != '\033' && c != '\012' && c != '\015' && c != '\b')) {
        if (term->sco_acs == 2)
          c |= 0x80;
        c |= CSET_SCOACS;
      } else {
        switch (term->cset_attr[term->cset]) {
          /*
           * Linedraw characters are different from 'ESC ( B'
           * only for a small range. For ones outside that
           * range, make sure we use the same font as well as
           * the same encoding.
           */
        case CSET_LINEDRW:
          if (term->ucsdata->unitab_ctrl[c] != 0xFF)
            c = term->ucsdata->unitab_ctrl[c];
          else
            c = ((unsigned char)c) | CSET_LINEDRW;
          break;

        case CSET_GBCHR:
          /* If UK-ASCII, make the '#' a LineDraw Pound */
          if (c == '#') {
            c = '}' | CSET_LINEDRW;
            break;
          }
        /*FALLTHROUGH*/ case CSET_ASCII:
          if (term->ucsdata->unitab_ctrl[c] != 0xFF)
            c = term->ucsdata->unitab_ctrl[c];
          else
            c = ((unsigned char)c) | CSET_ASCII;
          break;
        case CSET_SCOACS:
          if (c >= ' ')
            c = ((unsigned char)c) | CSET_SCOACS;
          break;
        }
      }
    }

    /*
     * How about C1 controls?
     * Explicitly ignore SCI (0x9a), which we don't translate to DECID.
     */
    if ((c & -32) == 0x80 && term->termstate < DO_CTRLS && !term->vt52_mode &&
        has_compat(VT220)) {
      if (c == 0x9a)
        c = 0;
      else {
        term->termstate = SEEN_ESC;
        term->esc_query = FALSE;
        c = '@' + (c & 0x1F);
      }
    }

    /* Or the GL control. */
    if (c == '\177' && term->termstate < DO_CTRLS && has_compat(OTHER)) {
      if (term->curs.x && !term->wrapnext)
        term->curs.x--;
      term->wrapnext = FALSE;
      /* destructive backspace might be disabled */
      if (!term->no_dbackspace) {
        check_boundary(term, term->curs.x, term->curs.y);
        check_boundary(term, term->curs.x + 1, term->curs.y);
        copy_termchar(
            scrlineptr(term->curs.y), term->curs.x, &term->erase_char);
      }
    } else
        /* Or normal C0 controls. */
        if ((c & ~0x1F) == 0 && term->termstate < DO_CTRLS) {
      switch (c) {
      case '\005': /* ENQ: terminal type query */
        /*
         * Strictly speaking this is VT100 but a VT100 defaults to
         * no response. Other terminals respond at their option.
         *
         * Don't put a CR in the default string as this tends to
         * upset some weird software.
         */
        compatibility(ANSIMIN);
        if (term->ldisc) {
          lpage_send(term->ldisc,
                     DEFAULT_CODEPAGE,
                     term->answerback,
                     term->answerbacklen,
                     0);
        }
        break;
      case '\007': /* BEL: Bell */
      {
        struct beeptime *newbeep;
        unsigned long ticks;

        ticks = GETTICKCOUNT();

        if (!term->beep_overloaded) {
          newbeep = snew(struct beeptime);
          newbeep->ticks = ticks;
          newbeep->next = NULL;
          if (!term->beephead)
            term->beephead = newbeep;
          else
            term->beeptail->next = newbeep;
          term->beeptail = newbeep;
          term->nbeeps++;
        }

        /*
         * Throw out any beeps that happened more than
         * t seconds ago.
         */
        while (term->beephead &&
               term->beephead->ticks < ticks - term->bellovl_t) {
          struct beeptime *tmp = term->beephead;
          term->beephead = tmp->next;
          sfree(tmp);
          if (!term->beephead)
            term->beeptail = NULL;
          term->nbeeps--;
        }

        if (term->bellovl && term->beep_overloaded &&
            ticks - term->lastbeep >= (unsigned)term->bellovl_s) {
          /*
           * If we're currently overloaded and the
           * last beep was more than s seconds ago,
           * leave overload mode.
           */
          term->beep_overloaded = FALSE;
        } else if (term->bellovl && !term->beep_overloaded &&
                   term->nbeeps >= term->bellovl_n) {
          /*
           * Now, if we have n or more beeps
           * remaining in the queue, go into overload
           * mode.
           */
          term->beep_overloaded = TRUE;
        }
        term->lastbeep = ticks;

        /*
         * Perform an actual beep if we're not overloaded.
         */
        if (!term->bellovl || !term->beep_overloaded) {
          do_beep(term->frontend, term->beep);

          if (term->beep == BELL_VISUAL) {
            term_schedule_vbell(term, FALSE, 0);
          }
        }
        seen_disp_event(term);
      } break;
      case '\b': /* BS: Back space */
        if (term->curs.x == 0 && (term->curs.y == 0 || term->wrap == 0))
          /* do nothing */;
        else if (term->curs.x == 0 && term->curs.y > 0)
          term->curs.x = term->cols - 1, term->curs.y--;
        else if (term->wrapnext)
          term->wrapnext = FALSE;
        else
          term->curs.x--;
        seen_disp_event(term);
        break;
      case '\016': /* LS1: Locking-shift one */
        compatibility(VT100);
        term->cset = 1;
        break;
      case '\017': /* LS0: Locking-shift zero */
        compatibility(VT100);
        term->cset = 0;
        break;
      case '\033': /* ESC: Escape */
        if (term->vt52_mode)
          term->termstate = VT52_ESC;
        else {
          compatibility(ANSIMIN);
          term->termstate = SEEN_ESC;
          term->esc_query = FALSE;
        }
        break;
      case '\015': /* CR: Carriage return */
        term->curs.x = 0;
        term->wrapnext = FALSE;
        seen_disp_event(term);

        if (term->crhaslf) {
          if (term->curs.y == term->marg_b)
            scroll(term, term->marg_t, term->marg_b, 1, TRUE);
          else if (term->curs.y < term->rows - 1)
            term->curs.y++;
        }
        if (term->logctx)
          logtraffic(term->logctx, (unsigned char)c, LGTYP_ASCII);
        break;
      case '\014': /* FF: Form feed */
        if (has_compat(SCOANSI)) {
          move(term, 0, 0, 0);
          erase_lots(term, FALSE, FALSE, TRUE);
          if (term->scroll_on_disp)
            term->disptop = 0;
          term->wrapnext = FALSE;
          seen_disp_event(term);
          break;
        }
      case '\013': /* VT: Line tabulation */
        compatibility(VT100);
      case '\012': /* LF: Line feed */
        if (term->curs.y == term->marg_b)
          scroll(term, term->marg_t, term->marg_b, 1, TRUE);
        else if (term->curs.y < term->rows - 1)
          term->curs.y++;
        if (term->lfhascr)
          term->curs.x = 0;
        term->wrapnext = FALSE;
        seen_disp_event(term);
        if (term->logctx)
          logtraffic(term->logctx, (unsigned char)c, LGTYP_ASCII);
        break;
      case '\t': /* HT: Character tabulation */
      {
        pos old_curs = term->curs;
        termline *ldata = scrlineptr(term->curs.y);

        do {
          term->curs.x++;
        } while (term->curs.x < term->cols - 1 && !term->tabs[term->curs.x]);

        if ((ldata->lattr & LATTR_MODE) != LATTR_NORM) {
          if (term->curs.x >= term->cols / 2)
            term->curs.x = term->cols / 2 - 1;
        } else {
          if (term->curs.x >= term->cols)
            term->curs.x = term->cols - 1;
        }

        check_selection(term, old_curs, term->curs);
      }
        seen_disp_event(term);
        break;
      }
    } else
      switch (term->termstate) {
      case TOPLEVEL:
        /* Only graphic characters get this far;
         * ctrls are stripped above */
        {
          termline *cline = scrlineptr(term->curs.y);
          int width = 0;
          if (DIRECT_CHAR(c))
            width = 1;
          if (!width)
            width = (term->cjk_ambig_wide ? mk_wcwidth_cjk((unsigned int)c)
                                          : mk_wcwidth((unsigned int)c));

          if (term->wrapnext && term->wrap && width > 0) {
            cline->lattr |= LATTR_WRAPPED;
            if (term->curs.y == term->marg_b)
              scroll(term, term->marg_t, term->marg_b, 1, TRUE);
            else if (term->curs.y < term->rows - 1)
              term->curs.y++;
            term->curs.x = 0;
            term->wrapnext = FALSE;
            cline = scrlineptr(term->curs.y);
          }
          if (term->insert && width > 0)
            insch(term, width);
          if (term->selstate != NO_SELECTION) {
            pos cursplus = term->curs;
            incpos(cursplus);
            check_selection(term, term->curs, cursplus);
          }
          if (((c & CSET_MASK) == CSET_ASCII || (c & CSET_MASK) == 0) &&
              term->logctx)
            logtraffic(term->logctx, (unsigned char)c, LGTYP_ASCII);

          switch (width) {
          case 2:
            /*
             * If we're about to display a double-width
             * character starting in the rightmost
             * column, then we do something special
             * instead. We must print a space in the
             * last column of the screen, then wrap;
             * and we also set LATTR_WRAPPED2 which
             * instructs subsequent cut-and-pasting not
             * only to splice this line to the one
             * after it, but to ignore the space in the
             * last character position as well.
             * (Because what was actually output to the
             * terminal was presumably just a sequence
             * of CJK characters, and we don't want a
             * space to be pasted in the middle of
             * those just because they had the
             * misfortune to start in the wrong parity
             * column. xterm concurs.)
             */
            check_boundary(term, term->curs.x, term->curs.y);
            check_boundary(term, term->curs.x + 2, term->curs.y);
            if (term->curs.x == term->cols - 1) {
              copy_termchar(cline, term->curs.x, &term->erase_char);
              cline->lattr |= LATTR_WRAPPED | LATTR_WRAPPED2;
              if (term->curs.y == term->marg_b)
                scroll(term, term->marg_t, term->marg_b, 1, TRUE);
              else if (term->curs.y < term->rows - 1)
                term->curs.y++;
              term->curs.x = 0;
              cline = scrlineptr(term->curs.y);
              /* Now we must check_boundary again, of course. */
              check_boundary(term, term->curs.x, term->curs.y);
              check_boundary(term, term->curs.x + 2, term->curs.y);
            }

            /* FULL-TERMCHAR */
            clear_cc(cline, term->curs.x);
            cline->chars[term->curs.x].chr = c;
            cline->chars[term->curs.x].attr = term->curr_attr;

            term->curs.x++;

            /* FULL-TERMCHAR */
            clear_cc(cline, term->curs.x);
            cline->chars[term->curs.x].chr = UCSWIDE;
            cline->chars[term->curs.x].attr = term->curr_attr;

            break;
          case 1:
            check_boundary(term, term->curs.x, term->curs.y);
            check_boundary(term, term->curs.x + 1, term->curs.y);

            /* FULL-TERMCHAR */
            clear_cc(cline, term->curs.x);
            cline->chars[term->curs.x].chr = c;
            cline->chars[term->curs.x].attr = term->curr_attr;

            break;
          case 0:
            if (term->curs.x > 0) {
              int x = term->curs.x - 1;

              /* If we're in wrapnext state, the character
               * to combine with is _here_, not to our left. */
              if (term->wrapnext)
                x++;

              /*
               * If the previous character is
               * UCSWIDE, back up another one.
               */
              if (cline->chars[x].chr == UCSWIDE) {
                assert(x > 0);
                x--;
              }

              add_cc(cline, x, c);
              seen_disp_event(term);
            }
            continue;
          default:
            continue;
          }
          term->curs.x++;
          if (term->curs.x == term->cols) {
            term->curs.x--;
            term->wrapnext = TRUE;
            if (term->wrap && term->vt52_mode) {
              cline->lattr |= LATTR_WRAPPED;
              if (term->curs.y == term->marg_b)
                scroll(term, term->marg_t, term->marg_b, 1, TRUE);
              else if (term->curs.y < term->rows - 1)
                term->curs.y++;
              term->curs.x = 0;
              term->wrapnext = FALSE;
            }
          }
          seen_disp_event(term);
        }
        break;

      case OSC_MAYBE_ST:
        /*
         * This state is virtually identical to SEEN_ESC, with the
         * exception that we have an OSC sequence in the pipeline,
         * and _if_ we see a backslash, we process it.
         */
        if (c == '\\') {
          do_osc(term);
          term->termstate = TOPLEVEL;
          break;
        }
        /* else fall through */
      case SEEN_ESC:
        if (c >= ' ' && c <= '/') {
          if (term->esc_query)
            term->esc_query = -1;
          else
            term->esc_query = c;
          break;
        }
        term->termstate = TOPLEVEL;
        switch (ANSI(c, term->esc_query)) {
        case '[': /* enter CSI mode */
          term->termstate = SEEN_CSI;
          term->esc_nargs = 1;
          term->esc_args[0] = ARG_DEFAULT;
          term->esc_query = FALSE;
          break;
        case ']': /* OSC: xterm escape sequences */
          /* Compatibility is nasty here, xterm, linux, decterm yuk! */
          compatibility(OTHER);
          term->termstate = SEEN_OSC;
          term->esc_args[0] = 0;
          break;
        case '7': /* DECSC: save cursor */
          compatibility(VT100);
          save_cursor(term, TRUE);
          break;
        case '8': /* DECRC: restore cursor */
          compatibility(VT100);
          save_cursor(term, FALSE);
          seen_disp_event(term);
          break;
        case '=': /* DECKPAM: Keypad application mode */
          compatibility(VT100);
          term->app_keypad_keys = TRUE;
          break;
        case '>': /* DECKPNM: Keypad numeric mode */
          compatibility(VT100);
          term->app_keypad_keys = FALSE;
          break;
        case 'D': /* IND: exactly equivalent to LF */
          compatibility(VT100);
          if (term->curs.y == term->marg_b)
            scroll(term, term->marg_t, term->marg_b, 1, TRUE);
          else if (term->curs.y < term->rows - 1)
            term->curs.y++;
          term->wrapnext = FALSE;
          seen_disp_event(term);
          break;
        case 'E': /* NEL: exactly equivalent to CR-LF */
          compatibility(VT100);
          term->curs.x = 0;
          if (term->curs.y == term->marg_b)
            scroll(term, term->marg_t, term->marg_b, 1, TRUE);
          else if (term->curs.y < term->rows - 1)
            term->curs.y++;
          term->wrapnext = FALSE;
          seen_disp_event(term);
          break;
        case 'M': /* RI: reverse index - backwards LF */
          compatibility(VT100);
          if (term->curs.y == term->marg_t)
            scroll(term, term->marg_t, term->marg_b, -1, TRUE);
          else if (term->curs.y > 0)
            term->curs.y--;
          term->wrapnext = FALSE;
          seen_disp_event(term);
          break;
        case 'Z': /* DECID: terminal type query */
          compatibility(VT100);
          if (term->ldisc)
            ldisc_send(
                term->ldisc, term->id_string, strlen(term->id_string), 0);
          break;
        case 'c': /* RIS: restore power-on settings */
          compatibility(VT100);
          power_on(term, TRUE);
          if (term->ldisc) /* cause ldisc to notice changes */
            ldisc_echoedit_update(term->ldisc);
          if (term->reset_132) {
            if (!term->no_remote_resize)
              request_resize(term->frontend, 80, term->rows);
            term->reset_132 = 0;
          }
          if (term->scroll_on_disp)
            term->disptop = 0;
          seen_disp_event(term);
          break;
        case 'H': /* HTS: set a tab */
          compatibility(VT100);
          term->tabs[term->curs.x] = TRUE;
          break;

        case ANSI('8', '#'): /* DECALN: fills screen with Es :-) */
          compatibility(VT100);
          {
            termline *ldata;
            int i, j;
            pos scrtop, scrbot;

            for (i = 0; i < term->rows; i++) {
              ldata = scrlineptr(i);
              check_line_size(term, ldata);
              for (j = 0; j < term->cols; j++) {
                copy_termchar(ldata, j, &term->basic_erase_char);
                ldata->chars[j].chr = 'E';
              }
              ldata->lattr = LATTR_NORM;
            }
            if (term->scroll_on_disp)
              term->disptop = 0;
            seen_disp_event(term);
            scrtop.x = scrtop.y = 0;
            scrbot.x = 0;
            scrbot.y = term->rows;
            check_selection(term, scrtop, scrbot);
          }
          break;

        case ANSI('3', '#'):
        case ANSI('4', '#'):
        case ANSI('5', '#'):
        case ANSI('6', '#'):
          compatibility(VT100);
          {
            int nlattr;
            termline *ldata;

            switch (ANSI(c, term->esc_query)) {
            case ANSI('3', '#'): /* DECDHL: 2*height, top */
              nlattr = LATTR_TOP;
              break;
            case ANSI('4', '#'): /* DECDHL: 2*height, bottom */
              nlattr = LATTR_BOT;
              break;
            case ANSI('5', '#'): /* DECSWL: normal */
              nlattr = LATTR_NORM;
              break;
            default: /* case ANSI('6', '#'): DECDWL: 2*width */
              nlattr = LATTR_WIDE;
              break;
            }
            ldata = scrlineptr(term->curs.y);
            check_line_size(term, ldata);
            ldata->lattr = nlattr;
          }
          break;
        /* GZD4: G0 designate 94-set */
        case ANSI('A', '('):
          compatibility(VT100);
          if (!term->no_remote_charset)
            term->cset_attr[0] = CSET_GBCHR;
          break;
        case ANSI('B', '('):
          compatibility(VT100);
          if (!term->no_remote_charset)
            term->cset_attr[0] = CSET_ASCII;
          break;
        case ANSI('0', '('):
          compatibility(VT100);
          if (!term->no_remote_charset)
            term->cset_attr[0] = CSET_LINEDRW;
          break;
        case ANSI('U', '('):
          compatibility(OTHER);
          if (!term->no_remote_charset)
            term->cset_attr[0] = CSET_SCOACS;
          break;
        /* G1D4: G1-designate 94-set */
        case ANSI('A', ')'):
          compatibility(VT100);
          if (!term->no_remote_charset)
            term->cset_attr[1] = CSET_GBCHR;
          break;
        case ANSI('B', ')'):
          compatibility(VT100);
          if (!term->no_remote_charset)
            term->cset_attr[1] = CSET_ASCII;
          break;
        case ANSI('0', ')'):
          compatibility(VT100);
          if (!term->no_remote_charset)
            term->cset_attr[1] = CSET_LINEDRW;
          break;
        case ANSI('U', ')'):
          compatibility(OTHER);
          if (!term->no_remote_charset)
            term->cset_attr[1] = CSET_SCOACS;
          break;
        /* DOCS: Designate other coding system */
        case ANSI('8', '%'): /* Old Linux code */
        case ANSI('G', '%'):
          compatibility(OTHER);
          if (!term->no_remote_charset)
            term->utf = 1;
          break;
        case ANSI('@', '%'):
          compatibility(OTHER);
          if (!term->no_remote_charset)
            term->utf = 0;
          break;
        }
        break;
      case SEEN_CSI:
        term->termstate = TOPLEVEL; /* default */
        if (isdigit(c)) {
          if (term->esc_nargs <= ARGS_MAX) {
            if (term->esc_args[term->esc_nargs - 1] == ARG_DEFAULT)
              term->esc_args[term->esc_nargs - 1] = 0;
            if (term->esc_args[term->esc_nargs - 1] <= UINT_MAX / 10 &&
                term->esc_args[term->esc_nargs - 1] * 10 <= UINT_MAX - c - '0')
              term->esc_args[term->esc_nargs - 1] =
                  10 * term->esc_args[term->esc_nargs - 1] + c - '0';
            else
              term->esc_args[term->esc_nargs - 1] = UINT_MAX;
          }
          term->termstate = SEEN_CSI;
        } else if (c == ';') {
          if (term->esc_nargs < ARGS_MAX)
            term->esc_args[term->esc_nargs++] = ARG_DEFAULT;
          term->termstate = SEEN_CSI;
        } else if (c < '@') {
          if (term->esc_query)
            term->esc_query = -1;
          else if (c == '?')
            term->esc_query = TRUE;
          else
            term->esc_query = c;
          term->termstate = SEEN_CSI;
        } else
#define CLAMP(arg, lim) ((arg) = ((arg) > (lim)) ? (lim) : (arg))
          switch (ANSI(c, term->esc_query)) {
          case 'A': /* CUU: move up N lines */
            CLAMP(term->esc_args[0], term->rows);
            move(term,
                 term->curs.x,
                 term->curs.y - def(term->esc_args[0], 1),
                 1);
            seen_disp_event(term);
            break;
          case 'e': /* VPR: move down N lines */
            compatibility(ANSI);
            /* FALLTHROUGH */
          case 'B': /* CUD: Cursor down */
            CLAMP(term->esc_args[0], term->rows);
            move(term,
                 term->curs.x,
                 term->curs.y + def(term->esc_args[0], 1),
                 1);
            seen_disp_event(term);
            break;
          case ANSI('c', '>'): /* DA: report xterm version */
            compatibility(OTHER);
            /* this reports xterm version 136 so that VIM can
               use the drag messages from the mouse reporting */
            if (term->ldisc)
              ldisc_send(term->ldisc, "\033[>0;136;0c", 11, 0);
            break;
          case 'a': /* HPR: move right N cols */
            compatibility(ANSI);
            /* FALLTHROUGH */
          case 'C': /* CUF: Cursor right */
            CLAMP(term->esc_args[0], term->cols);
            move(term,
                 term->curs.x + def(term->esc_args[0], 1),
                 term->curs.y,
                 1);
            seen_disp_event(term);
            break;
          case 'D': /* CUB: move left N cols */
            CLAMP(term->esc_args[0], term->cols);
            move(term,
                 term->curs.x - def(term->esc_args[0], 1),
                 term->curs.y,
                 1);
            seen_disp_event(term);
            break;
          case 'E': /* CNL: move down N lines and CR */
            compatibility(ANSI);
            CLAMP(term->esc_args[0], term->rows);
            move(term, 0, term->curs.y + def(term->esc_args[0], 1), 1);
            seen_disp_event(term);
            break;
          case 'F': /* CPL: move up N lines and CR */
            compatibility(ANSI);
            CLAMP(term->esc_args[0], term->rows);
            move(term, 0, term->curs.y - def(term->esc_args[0], 1), 1);
            seen_disp_event(term);
            break;
          case 'G': /* CHA */
          case '`': /* HPA: set horizontal posn */
            compatibility(ANSI);
            CLAMP(term->esc_args[0], term->cols);
            move(term, def(term->esc_args[0], 1) - 1, term->curs.y, 0);
            seen_disp_event(term);
            break;
          case 'd': /* VPA: set vertical posn */
            compatibility(ANSI);
            CLAMP(term->esc_args[0], term->rows);
            move(term,
                 term->curs.x,
                 ((term->dec_om ? term->marg_t : 0) +
                  def(term->esc_args[0], 1) - 1),
                 (term->dec_om ? 2 : 0));
            seen_disp_event(term);
            break;
          case 'H': /* CUP */
          case 'f': /* HVP: set horz and vert posns at once */
            if (term->esc_nargs < 2)
              term->esc_args[1] = ARG_DEFAULT;
            CLAMP(term->esc_args[0], term->rows);
            CLAMP(term->esc_args[1], term->cols);
            move(term,
                 def(term->esc_args[1], 1) - 1,
                 ((term->dec_om ? term->marg_t : 0) +
                  def(term->esc_args[0], 1) - 1),
                 (term->dec_om ? 2 : 0));
            seen_disp_event(term);
            break;
          case 'J': /* ED: erase screen or parts of it */
          {
            unsigned int i = def(term->esc_args[0], 0);
            if (i == 3) {
              /* Erase Saved Lines (xterm)
               * This follows Thomas Dickey's xterm. */
              if (!term->no_remote_clearscroll)
                term_clrsb(term);
            } else {
              i++;
              if (i > 3)
                i = 0;
              erase_lots(term, FALSE, !!(i & 2), !!(i & 1));
            }
          }
            if (term->scroll_on_disp)
              term->disptop = 0;
            seen_disp_event(term);
            break;
          case 'K': /* EL: erase line or parts of it */
          {
            unsigned int i = def(term->esc_args[0], 0) + 1;
            if (i > 3)
              i = 0;
            erase_lots(term, TRUE, !!(i & 2), !!(i & 1));
          }
            seen_disp_event(term);
            break;
          case 'L': /* IL: insert lines */
            compatibility(VT102);
            CLAMP(term->esc_args[0], term->rows);
            if (term->curs.y <= term->marg_b)
              scroll(term,
                     term->curs.y,
                     term->marg_b,
                     -def(term->esc_args[0], 1),
                     FALSE);
            seen_disp_event(term);
            break;
          case 'M': /* DL: delete lines */
            compatibility(VT102);
            CLAMP(term->esc_args[0], term->rows);
            if (term->curs.y <= term->marg_b)
              scroll(term,
                     term->curs.y,
                     term->marg_b,
                     def(term->esc_args[0], 1),
                     TRUE);
            seen_disp_event(term);
            break;
          case '@': /* ICH: insert chars */
            /* XXX VTTEST says this is vt220, vt510 manual says vt102 */
            compatibility(VT102);
            CLAMP(term->esc_args[0], term->cols);
            insch(term, def(term->esc_args[0], 1));
            seen_disp_event(term);
            break;
          case 'P': /* DCH: delete chars */
            compatibility(VT102);
            CLAMP(term->esc_args[0], term->cols);
            insch(term, -def(term->esc_args[0], 1));
            seen_disp_event(term);
            break;
          case 'c': /* DA: terminal type query */
            compatibility(VT100);
            /* This is the response for a VT102 */
            if (term->ldisc)
              ldisc_send(
                  term->ldisc, term->id_string, strlen(term->id_string), 0);
            break;
          case 'n': /* DSR: cursor position query */
            if (term->ldisc) {
              if (term->esc_args[0] == 6) {
                char buf[32];
                sprintf(buf, "\033[%d;%dR", term->curs.y + 1, term->curs.x + 1);
                ldisc_send(term->ldisc, buf, strlen(buf), 0);
              } else if (term->esc_args[0] == 5) {
                ldisc_send(term->ldisc, "\033[0n", 4, 0);
              }
            }
            break;
          case 'h': /* SM: toggle modes to high */
          case ANSI_QUE('h'):
            compatibility(VT100);
            {
              int i;
              for (i = 0; i < term->esc_nargs; i++)
                toggle_mode(term, term->esc_args[i], term->esc_query, TRUE);
            }
            break;
          case 'i': /* MC: Media copy */
          case ANSI_QUE('i'):
            compatibility(VT100);
            {
              char *printer;
              if (term->esc_nargs != 1)
                break;
              if (term->esc_args[0] == 5 &&
                  (printer = conf_get_str(term->conf, CONF_printer))[0]) {
                term->printing = TRUE;
                term->only_printing = !term->esc_query;
                term->print_state = 0;
                term_print_setup(term, printer);
              } else if (term->esc_args[0] == 4 && term->printing) {
                term_print_finish(term);
              }
            }
            break;
          case 'l': /* RM: toggle modes to low */
          case ANSI_QUE('l'):
            compatibility(VT100);
            {
              int i;
              for (i = 0; i < term->esc_nargs; i++)
                toggle_mode(term, term->esc_args[i], term->esc_query, FALSE);
            }
            break;
          case 'g': /* TBC: clear tabs */
            compatibility(VT100);
            if (term->esc_nargs == 1) {
              if (term->esc_args[0] == 0) {
                term->tabs[term->curs.x] = FALSE;
              } else if (term->esc_args[0] == 3) {
                int i;
                for (i = 0; i < term->cols; i++)
                  term->tabs[i] = FALSE;
              }
            }
            break;
          case 'r': /* DECSTBM: set scroll margins */
            compatibility(VT100);
            if (term->esc_nargs <= 2) {
              int top, bot;
              CLAMP(term->esc_args[0], term->rows);
              CLAMP(term->esc_args[1], term->rows);
              top = def(term->esc_args[0], 1) - 1;
              bot = (term->esc_nargs <= 1 || term->esc_args[1] == 0
                         ? term->rows
                         : def(term->esc_args[1], term->rows)) -
                    1;
              if (bot >= term->rows)
                bot = term->rows - 1;
              /* VTTEST Bug 9 - if region is less than 2 lines
               * don't change region.
               */
              if (bot - top > 0) {
                term->marg_t = top;
                term->marg_b = bot;
                term->curs.x = 0;
                /*
                 * I used to think the cursor should be
                 * placed at the top of the newly marginned
                 * area. Apparently not: VMS TPU falls over
                 * if so.
                 *
                 * Well actually it should for
                 * Origin mode - RDB
                 */
                term->curs.y = (term->dec_om ? term->marg_t : 0);
                seen_disp_event(term);
              }
            }
            break;
          case 'm': /* SGR: set graphics rendition */
          {
            /*
             * A VT100 without the AVO only had one
             * attribute, either underline or
             * reverse video depending on the
             * cursor type, this was selected by
             * CSI 7m.
             *
             * case 2:
             *  This is sometimes DIM, eg on the
             *  GIGI and Linux
             * case 8:
             *  This is sometimes INVIS various ANSI.
             * case 21:
             *  This like 22 disables BOLD, DIM and INVIS
             *
             * The ANSI colours appear on any
             * terminal that has colour (obviously)
             * but the interaction between sgr0 and
             * the colours varies but is usually
             * related to the background colour
             * erase item. The interaction between
             * colour attributes and the mono ones
             * is also very implementation
             * dependent.
             *
             * The 39 and 49 attributes are likely
             * to be unimplemented.
             */
            int i;
            for (i = 0; i < term->esc_nargs; i++) {
              switch (def(term->esc_args[i], 0)) {
              case 0: /* restore defaults */
                term->curr_attr = term->default_attr;
                break;
              case 1: /* enable bold */
                compatibility(VT100AVO);
                term->curr_attr |= ATTR_BOLD;
                break;
              case 21: /* (enable double underline) */
                compatibility(OTHER);
              case 4: /* enable underline */
                compatibility(VT100AVO);
                term->curr_attr |= ATTR_UNDER;
                break;
              case 5: /* enable blink */
                compatibility(VT100AVO);
                term->curr_attr |= ATTR_BLINK;
                break;
              case 6: /* SCO light bkgrd */
                compatibility(SCOANSI);
                term->blink_is_real = FALSE;
                term->curr_attr |= ATTR_BLINK;
                term_schedule_tblink(term);
                break;
              case 7: /* enable reverse video */
                term->curr_attr |= ATTR_REVERSE;
                break;
              case 10: /* SCO acs off */
                compatibility(SCOANSI);
                if (term->no_remote_charset)
                  break;
                term->sco_acs = 0;
                break;
              case 11: /* SCO acs on */
                compatibility(SCOANSI);
                if (term->no_remote_charset)
                  break;
                term->sco_acs = 1;
                break;
              case 12: /* SCO acs on, |0x80 */
                compatibility(SCOANSI);
                if (term->no_remote_charset)
                  break;
                term->sco_acs = 2;
                break;
              case 22: /* disable bold */
                compatibility2(OTHER, VT220);
                term->curr_attr &= ~ATTR_BOLD;
                break;
              case 24: /* disable underline */
                compatibility2(OTHER, VT220);
                term->curr_attr &= ~ATTR_UNDER;
                break;
              case 25: /* disable blink */
                compatibility2(OTHER, VT220);
                term->curr_attr &= ~ATTR_BLINK;
                break;
              case 27: /* disable reverse video */
                compatibility2(OTHER, VT220);
                term->curr_attr &= ~ATTR_REVERSE;
                break;
              case 30:
              case 31:
              case 32:
              case 33:
              case 34:
              case 35:
              case 36:
              case 37:
                /* foreground */
                term->curr_attr &= ~ATTR_FGMASK;
                term->curr_attr |= (term->esc_args[i] - 30) << ATTR_FGSHIFT;
                break;
              case 90:
              case 91:
              case 92:
              case 93:
              case 94:
              case 95:
              case 96:
              case 97:
                /* aixterm-style bright foreground */
                term->curr_attr &= ~ATTR_FGMASK;
                term->curr_attr |=
                    ((term->esc_args[i] - 90 + 8) << ATTR_FGSHIFT);
                break;
              case 39: /* default-foreground */
                term->curr_attr &= ~ATTR_FGMASK;
                term->curr_attr |= ATTR_DEFFG;
                break;
              case 40:
              case 41:
              case 42:
              case 43:
              case 44:
              case 45:
              case 46:
              case 47:
                /* background */
                term->curr_attr &= ~ATTR_BGMASK;
                term->curr_attr |= (term->esc_args[i] - 40) << ATTR_BGSHIFT;
                break;
              case 100:
              case 101:
              case 102:
              case 103:
              case 104:
              case 105:
              case 106:
              case 107:
                /* aixterm-style bright background */
                term->curr_attr &= ~ATTR_BGMASK;
                term->curr_attr |=
                    ((term->esc_args[i] - 100 + 8) << ATTR_BGSHIFT);
                break;
              case 49: /* default-background */
                term->curr_attr &= ~ATTR_BGMASK;
                term->curr_attr |= ATTR_DEFBG;
                break;
              case 38: /* xterm 256-colour mode */
                if (i + 2 < term->esc_nargs && term->esc_args[i + 1] == 5) {
                  term->curr_attr &= ~ATTR_FGMASK;
                  term->curr_attr |=
                      ((term->esc_args[i + 2] & 0xFF) << ATTR_FGSHIFT);
                  i += 2;
                }
                break;
              case 48: /* xterm 256-colour mode */
                if (i + 2 < term->esc_nargs && term->esc_args[i + 1] == 5) {
                  term->curr_attr &= ~ATTR_BGMASK;
                  term->curr_attr |=
                      ((term->esc_args[i + 2] & 0xFF) << ATTR_BGSHIFT);
                  i += 2;
                }
                break;
              }
            }
            set_erase_char(term);
          } break;
          case 's': /* save cursor */
            save_cursor(term, TRUE);
            break;
          case 'u': /* restore cursor */
            save_cursor(term, FALSE);
            seen_disp_event(term);
            break;
          case 't': /* DECSLPP: set page size - ie window height */
            /*
             * VT340/VT420 sequence DECSLPP, DEC only allows values
             *  24/25/36/48/72/144 other emulators (eg dtterm) use
             * illegal values (eg first arg 1..9) for window changing
             * and reports.
             */
            if (term->esc_nargs <= 1 &&
                (term->esc_args[0] < 1 || term->esc_args[0] >= 24)) {
              compatibility(VT340TEXT);
              if (!term->no_remote_resize)
                request_resize(
                    term->frontend, term->cols, def(term->esc_args[0], 24));
              deselect(term);
            } else if (term->esc_nargs >= 1 && term->esc_args[0] >= 1 &&
                       term->esc_args[0] < 24) {
              compatibility(OTHER);

              switch (term->esc_args[0]) {
                int x, y, len;
                char buf[80];
                const char *p;
              case 1:
                set_iconic(term->frontend, FALSE);
                break;
              case 2:
                set_iconic(term->frontend, TRUE);
                break;
              case 3:
                if (term->esc_nargs >= 3) {
                  if (!term->no_remote_resize)
                    move_window(term->frontend,
                                def(term->esc_args[1], 0),
                                def(term->esc_args[2], 0));
                }
                break;
              case 4:
                /* We should resize the window to a given
                 * size in pixels here, but currently our
                 * resizing code isn't healthy enough to
                 * manage it. */
                break;
              case 5:
                /* move to top */
                set_zorder(term->frontend, TRUE);
                break;
              case 6:
                /* move to bottom */
                set_zorder(term->frontend, FALSE);
                break;
              case 7:
                refresh_window(term->frontend);
                break;
              case 8:
                if (term->esc_nargs >= 3) {
                  if (!term->no_remote_resize)
                    request_resize(term->frontend,
                                   def(term->esc_args[2], term->conf_width),
                                   def(term->esc_args[1], term->conf_height));
                }
                break;
              case 9:
                if (term->esc_nargs >= 2)
                  set_zoomed(term->frontend, term->esc_args[1] ? TRUE : FALSE);
                break;
              case 11:
                if (term->ldisc)
                  ldisc_send(term->ldisc,
                             is_iconic(term->frontend) ? "\033[2t" : "\033[1t",
                             4,
                             0);
                break;
              case 13:
                if (term->ldisc) {
                  get_window_pos(term->frontend, &x, &y);
                  len = sprintf(buf, "\033[3;%u;%ut", (unsigned)x, (unsigned)y);
                  ldisc_send(term->ldisc, buf, len, 0);
                }
                break;
              case 14:
                if (term->ldisc) {
                  get_window_pixels(term->frontend, &x, &y);
                  len = sprintf(buf, "\033[4;%d;%dt", y, x);
                  ldisc_send(term->ldisc, buf, len, 0);
                }
                break;
              case 18:
                if (term->ldisc) {
                  len = sprintf(buf, "\033[8;%d;%dt", term->rows, term->cols);
                  ldisc_send(term->ldisc, buf, len, 0);
                }
                break;
              case 19:
                /*
                 * Hmmm. Strictly speaking we
                 * should return `the size of the
                 * screen in characters', but
                 * that's not easy: (a) window
                 * furniture being what it is it's
                 * hard to compute, and (b) in
                 * resize-font mode maximising the
                 * window wouldn't change the
                 * number of characters. *shrug*. I
                 * think we'll ignore it for the
                 * moment and see if anyone
                 * complains, and then ask them
                 * what they would like it to do.
                 */
                break;
              case 20:
                if (term->ldisc && term->remote_qtitle_action != TITLE_NONE) {
                  if (term->remote_qtitle_action == TITLE_REAL)
                    p = get_window_title(term->frontend, TRUE);
                  else
                    p = EMPTY_WINDOW_TITLE;
                  len = strlen(p);
                  ldisc_send(term->ldisc, "\033]L", 3, 0);
                  ldisc_send(term->ldisc, p, len, 0);
                  ldisc_send(term->ldisc, "\033\\", 2, 0);
                }
                break;
              case 21:
                if (term->ldisc && term->remote_qtitle_action != TITLE_NONE) {
                  if (term->remote_qtitle_action == TITLE_REAL)
                    p = get_window_title(term->frontend, FALSE);
                  else
                    p = EMPTY_WINDOW_TITLE;
                  len = strlen(p);
                  ldisc_send(term->ldisc, "\033]l", 3, 0);
                  ldisc_send(term->ldisc, p, len, 0);
                  ldisc_send(term->ldisc, "\033\\", 2, 0);
                }
                break;
              }
            }
            break;
          case 'S': /* SU: Scroll up */
            CLAMP(term->esc_args[0], term->rows);
            compatibility(SCOANSI);
            scroll(term,
                   term->marg_t,
                   term->marg_b,
                   def(term->esc_args[0], 1),
                   TRUE);
            term->wrapnext = FALSE;
            seen_disp_event(term);
            break;
          case 'T': /* SD: Scroll down */
            CLAMP(term->esc_args[0], term->rows);
            compatibility(SCOANSI);
            scroll(term,
                   term->marg_t,
                   term->marg_b,
                   -def(term->esc_args[0], 1),
                   TRUE);
            term->wrapnext = FALSE;
            seen_disp_event(term);
            break;
          case ANSI('|', '*'): /* DECSNLS */
            /*
             * Set number of lines on screen
             * VT420 uses VGA like hardware and can
             * support any size in reasonable range
             * (24..49 AIUI) with no default specified.
             */
            compatibility(VT420);
            if (term->esc_nargs == 1 && term->esc_args[0] > 0) {
              if (!term->no_remote_resize)
                request_resize(term->frontend,
                               term->cols,
                               def(term->esc_args[0], term->conf_height));
              deselect(term);
            }
            break;
          case ANSI('|', '$'): /* DECSCPP */
            /*
             * Set number of columns per page
             * Docs imply range is only 80 or 132, but
             * I'll allow any.
             */
            compatibility(VT340TEXT);
            if (term->esc_nargs <= 1) {
              if (!term->no_remote_resize)
                request_resize(term->frontend,
                               def(term->esc_args[0], term->conf_width),
                               term->rows);
              deselect(term);
            }
            break;
          case 'X': /* ECH: write N spaces w/o moving cursor */
            /* XXX VTTEST says this is vt220, vt510 manual
             * says vt100 */
            compatibility(ANSIMIN);
            CLAMP(term->esc_args[0], term->cols);
            {
              int n = def(term->esc_args[0], 1);
              pos cursplus;
              int p = term->curs.x;
              termline *cline = scrlineptr(term->curs.y);

              if (n > term->cols - term->curs.x)
                n = term->cols - term->curs.x;
              cursplus = term->curs;
              cursplus.x += n;
              check_boundary(term, term->curs.x, term->curs.y);
              check_boundary(term, term->curs.x + n, term->curs.y);
              check_selection(term, term->curs, cursplus);
              while (n--)
                copy_termchar(cline, p++, &term->erase_char);
              seen_disp_event(term);
            }
            break;
          case 'x': /* DECREQTPARM: report terminal characteristics */
            compatibility(VT100);
            if (term->ldisc) {
              char buf[32];
              int i = def(term->esc_args[0], 0);
              if (i == 0 || i == 1) {
                strcpy(buf, "\033[2;1;1;112;112;1;0x");
                buf[2] += i;
                ldisc_send(term->ldisc, buf, 20, 0);
              }
            }
            break;
          case 'Z': /* CBT */
            compatibility(OTHER);
            CLAMP(term->esc_args[0], term->cols);
            {
              int i = def(term->esc_args[0], 1);
              pos old_curs = term->curs;

              for (; i > 0 && term->curs.x > 0; i--) {
                do {
                  term->curs.x--;
                } while (term->curs.x > 0 && !term->tabs[term->curs.x]);
              }
              check_selection(term, old_curs, term->curs);
            }
            break;
          case ANSI('c', '='): /* Hide or Show Cursor */
            compatibility(SCOANSI);
            switch (term->esc_args[0]) {
            case 0: /* hide cursor */
              term->cursor_on = FALSE;
              break;
            case 1: /* restore cursor */
              term->big_cursor = FALSE;
              term->cursor_on = TRUE;
              break;
            case 2: /* block cursor */
              term->big_cursor = TRUE;
              term->cursor_on = TRUE;
              break;
            }
            break;
          case ANSI('C', '='):
            /*
             * set cursor start on scanline esc_args[0] and
             * end on scanline esc_args[1].If you set
             * the bottom scan line to a value less than
             * the top scan line, the cursor will disappear.
             */
            compatibility(SCOANSI);
            if (term->esc_nargs >= 2) {
              if (term->esc_args[0] > term->esc_args[1])
                term->cursor_on = FALSE;
              else
                term->cursor_on = TRUE;
            }
            break;
          case ANSI('D', '='):
            compatibility(SCOANSI);
            term->blink_is_real = FALSE;
            term_schedule_tblink(term);
            if (term->esc_args[0] >= 1)
              term->curr_attr |= ATTR_BLINK;
            else
              term->curr_attr &= ~ATTR_BLINK;
            break;
          case ANSI('E', '='):
            compatibility(SCOANSI);
            term->blink_is_real = (term->esc_args[0] >= 1);
            term_schedule_tblink(term);
            break;
          case ANSI('F', '='): /* set normal foreground */
            compatibility(SCOANSI);
            if (term->esc_args[0] < 16) {
              long colour = (sco2ansicolour[term->esc_args[0] & 0x7] |
                             (term->esc_args[0] & 0x8))
                            << ATTR_FGSHIFT;
              term->curr_attr &= ~ATTR_FGMASK;
              term->curr_attr |= colour;
              term->default_attr &= ~ATTR_FGMASK;
              term->default_attr |= colour;
              set_erase_char(term);
            }
            break;
          case ANSI('G', '='): /* set normal background */
            compatibility(SCOANSI);
            if (term->esc_args[0] < 16) {
              long colour = (sco2ansicolour[term->esc_args[0] & 0x7] |
                             (term->esc_args[0] & 0x8))
                            << ATTR_BGSHIFT;
              term->curr_attr &= ~ATTR_BGMASK;
              term->curr_attr |= colour;
              term->default_attr &= ~ATTR_BGMASK;
              term->default_attr |= colour;
              set_erase_char(term);
            }
            break;
          case ANSI('L', '='):
            compatibility(SCOANSI);
            term->use_bce = (term->esc_args[0] <= 0);
            set_erase_char(term);
            break;
          case ANSI('p', '"'): /* DECSCL: set compat level */
            /*
             * Allow the host to make this emulator a
             * 'perfect' VT102. This first appeared in
             * the VT220, but we do need to get back to
             * PuTTY mode so I won't check it.
             *
             * The arg in 40..42,50 are a PuTTY extension.
             * The 2nd arg, 8bit vs 7bit is not checked.
             *
             * Setting VT102 mode should also change
             * the Fkeys to generate PF* codes as a
             * real VT102 has no Fkeys. The VT220 does
             * this, F11..F13 become ESC,BS,LF other
             * Fkeys send nothing.
             *
             * Note ESC c will NOT change this!
             */

            switch (term->esc_args[0]) {
            case 61:
              term->compatibility_level &= ~TM_VTXXX;
              term->compatibility_level |= TM_VT102;
              break;
            case 62:
              term->compatibility_level &= ~TM_VTXXX;
              term->compatibility_level |= TM_VT220;
              break;

            default:
              if (term->esc_args[0] > 60 && term->esc_args[0] < 70)
                term->compatibility_level |= TM_VTXXX;
              break;

            case 40:
              term->compatibility_level &= TM_VTXXX;
              break;
            case 41:
              term->compatibility_level = TM_PUTTY;
              break;
            case 42:
              term->compatibility_level = TM_SCOANSI;
              break;

            case ARG_DEFAULT:
              term->compatibility_level = TM_PUTTY;
              break;
            case 50:
              break;
            }

            /* Change the response to CSI c */
            if (term->esc_args[0] == 50) {
              int i;
              char lbuf[64];
              strcpy(term->id_string, "\033[?");
              for (i = 1; i < term->esc_nargs; i++) {
                if (i != 1)
                  strcat(term->id_string, ";");
                sprintf(lbuf, "%u", term->esc_args[i]);
                strcat(term->id_string, lbuf);
              }
              strcat(term->id_string, "c");
            }
#if 0
			/* Is this a good idea ? 
			 * Well we should do a soft reset at this point ...
			 */
			if (!has_compat(VT420) && has_compat(VT100)) {
			    if (!term->no_remote_resize) {
				if (term->reset_132)
				    request_resize(132, 24);
				else
				    request_resize(80, 24);
			    }
			}
#endif
            break;
          }
        break;
      case SEEN_OSC:
        term->osc_w = FALSE;
        switch (c) {
        case 'P': /* Linux palette sequence */
          term->termstate = SEEN_OSC_P;
          term->osc_strlen = 0;
          break;
        case 'R': /* Linux palette reset */
          palette_reset(term->frontend);
          term_invalidate(term);
          term->termstate = TOPLEVEL;
          break;
        case 'W': /* word-set */
          term->termstate = SEEN_OSC_W;
          term->osc_w = TRUE;
          break;
        case '0':
        case '1':
        case '2':
        case '3':
        case '4':
        case '5':
        case '6':
        case '7':
        case '8':
        case '9':
          if (term->esc_args[0] <= UINT_MAX / 10 &&
              term->esc_args[0] * 10 <= UINT_MAX - c - '0')
            term->esc_args[0] = 10 * term->esc_args[0] + c - '0';
          else
            term->esc_args[0] = UINT_MAX;
          break;
        case 'L':
          /*
           * Grotty hack to support xterm and DECterm title
           * sequences concurrently.
           */
          if (term->esc_args[0] == 2) {
            term->esc_args[0] = 1;
            break;
          }
          /* else fall through */
        default:
          term->termstate = OSC_STRING;
          term->osc_strlen = 0;
        }
        break;
      case OSC_STRING:
        /*
         * This OSC stuff is EVIL. It takes just one character to get into
         * sysline mode and it's not initially obvious how to get out.
         * So I've added CR and LF as string aborts.
         * This shouldn't effect compatibility as I believe embedded
         * control characters are supposed to be interpreted (maybe?)
         * and they don't display anything useful anyway.
         *
         * -- RDB
         */
        if (c == '\012' || c == '\015') {
          term->termstate = TOPLEVEL;
        } else if (c == 0234 || c == '\007') {
          /*
           * These characters terminate the string; ST and BEL
           * terminate the sequence and trigger instant
           * processing of it, whereas ESC goes back to SEEN_ESC
           * mode unless it is followed by \, in which case it is
           * synonymous with ST in the first place.
           */
          do_osc(term);
          term->termstate = TOPLEVEL;
        } else if (c == '\033')
          term->termstate = OSC_MAYBE_ST;
        else if (term->osc_strlen < OSC_STR_MAX)
          term->osc_string[term->osc_strlen++] = (char)c;
        break;
      case SEEN_OSC_P: {
        int max = (term->osc_strlen == 0 ? 21 : 15);
        int val;
        if ((int)c >= '0' && (int)c <= '9')
          val = c - '0';
        else if ((int)c >= 'A' && (int)c <= 'A' + max - 10)
          val = c - 'A' + 10;
        else if ((int)c >= 'a' && (int)c <= 'a' + max - 10)
          val = c - 'a' + 10;
        else {
          term->termstate = TOPLEVEL;
          break;
        }
        term->osc_string[term->osc_strlen++] = val;
        if (term->osc_strlen >= 7) {
          palette_set(term->frontend,
                      term->osc_string[0],
                      term->osc_string[1] * 16 + term->osc_string[2],
                      term->osc_string[3] * 16 + term->osc_string[4],
                      term->osc_string[5] * 16 + term->osc_string[6]);
          term_invalidate(term);
          term->termstate = TOPLEVEL;
        }
      } break;
      case SEEN_OSC_W:
        switch (c) {
        case '0':
        case '1':
        case '2':
        case '3':
        case '4':
        case '5':
        case '6':
        case '7':
        case '8':
        case '9':
          if (term->esc_args[0] <= UINT_MAX / 10 &&
              term->esc_args[0] * 10 <= UINT_MAX - c - '0')
            term->esc_args[0] = 10 * term->esc_args[0] + c - '0';
          else
            term->esc_args[0] = UINT_MAX;
          break;
        default:
          term->termstate = OSC_STRING;
          term->osc_strlen = 0;
        }
        break;
      case VT52_ESC:
        term->termstate = TOPLEVEL;
        seen_disp_event(term);
        switch (c) {
        case 'A':
          move(term, term->curs.x, term->curs.y - 1, 1);
          break;
        case 'B':
          move(term, term->curs.x, term->curs.y + 1, 1);
          break;
        case 'C':
          move(term, term->curs.x + 1, term->curs.y, 1);
          break;
        case 'D':
          move(term, term->curs.x - 1, term->curs.y, 1);
          break;
          /*
           * From the VT100 Manual
           * NOTE: The special graphics characters in the VT100
           *       are different from those in the VT52
           *
           * From VT102 manual:
           *       137 _  Blank             - Same
           *       140 `  Reserved          - Humm.
           *       141 a  Solid rectangle   - Similar
           *       142 b  1/                - Top half of fraction for the
           *       143 c  3/                - subscript numbers below.
           *       144 d  5/
           *       145 e  7/
           *       146 f  Degrees           - Same
           *       147 g  Plus or minus     - Same
           *       150 h  Right arrow
           *       151 i  Ellipsis (dots)
           *       152 j  Divide by
           *       153 k  Down arrow
           *       154 l  Bar at scan 0
           *       155 m  Bar at scan 1
           *       156 n  Bar at scan 2
           *       157 o  Bar at scan 3     - Similar
           *       160 p  Bar at scan 4     - Similar
           *       161 q  Bar at scan 5     - Similar
           *       162 r  Bar at scan 6     - Same
           *       163 s  Bar at scan 7     - Similar
           *       164 t  Subscript 0
           *       165 u  Subscript 1
           *       166 v  Subscript 2
           *       167 w  Subscript 3
           *       170 x  Subscript 4
           *       171 y  Subscript 5
           *       172 z  Subscript 6
           *       173 {  Subscript 7
           *       174 |  Subscript 8
           *       175 }  Subscript 9
           *       176 ~  Paragraph
           *
           */
        case 'F':
          term->cset_attr[term->cset = 0] = CSET_LINEDRW;
          break;
        case 'G':
          term->cset_attr[term->cset = 0] = CSET_ASCII;
          break;
        case 'H':
          move(term, 0, 0, 0);
          break;
        case 'I':
          if (term->curs.y == 0)
            scroll(term, 0, term->rows - 1, -1, TRUE);
          else if (term->curs.y > 0)
            term->curs.y--;
          term->wrapnext = FALSE;
          break;
        case 'J':
          erase_lots(term, FALSE, FALSE, TRUE);
          if (term->scroll_on_disp)
            term->disptop = 0;
          break;
        case 'K':
          erase_lots(term, TRUE, FALSE, TRUE);
          break;
#if 0
		  case 'V':
		    /* XXX Print cursor line */
		    break;
		  case 'W':
		    /* XXX Start controller mode */
		    break;
		  case 'X':
		    /* XXX Stop controller mode */
		    break;
#endif
        case 'Y':
          term->termstate = VT52_Y1;
          break;
        case 'Z':
          if (term->ldisc)
            ldisc_send(term->ldisc, "\033/Z", 3, 0);
          break;
        case '=':
          term->app_keypad_keys = TRUE;
          break;
        case '>':
          term->app_keypad_keys = FALSE;
          break;
        case '<':
          /* XXX This should switch to VT100 mode not current or default
           *     VT mode. But this will only have effect in a VT220+
           *     emulation.
           */
          term->vt52_mode = FALSE;
          term->blink_is_real = term->blinktext;
          term_schedule_tblink(term);
          break;
#if 0
		  case '^':
		    /* XXX Enter auto print mode */
		    break;
		  case '_':
		    /* XXX Exit auto print mode */
		    break;
		  case ']':
		    /* XXX Print screen */
		    break;
#endif

#ifdef VT52_PLUS
        case 'E':
          /* compatibility(ATARI) */
          move(term, 0, 0, 0);
          erase_lots(term, FALSE, FALSE, TRUE);
          if (term->scroll_on_disp)
            term->disptop = 0;
          break;
        case 'L':
          /* compatibility(ATARI) */
          if (term->curs.y <= term->marg_b)
            scroll(term, term->curs.y, term->marg_b, -1, FALSE);
          break;
        case 'M':
          /* compatibility(ATARI) */
          if (term->curs.y <= term->marg_b)
            scroll(term, term->curs.y, term->marg_b, 1, TRUE);
          break;
        case 'b':
          /* compatibility(ATARI) */
          term->termstate = VT52_FG;
          break;
        case 'c':
          /* compatibility(ATARI) */
          term->termstate = VT52_BG;
          break;
        case 'd':
          /* compatibility(ATARI) */
          erase_lots(term, FALSE, TRUE, FALSE);
          if (term->scroll_on_disp)
            term->disptop = 0;
          break;
        case 'e':
          /* compatibility(ATARI) */
          term->cursor_on = TRUE;
          break;
        case 'f':
          /* compatibility(ATARI) */
          term->cursor_on = FALSE;
          break;
          /* case 'j': Save cursor position - broken on ST */
          /* case 'k': Restore cursor position */
        case 'l':
          /* compatibility(ATARI) */
          erase_lots(term, TRUE, TRUE, TRUE);
          term->curs.x = 0;
          term->wrapnext = FALSE;
          break;
        case 'o':
          /* compatibility(ATARI) */
          erase_lots(term, TRUE, TRUE, FALSE);
          break;
        case 'p':
          /* compatibility(ATARI) */
          term->curr_attr |= ATTR_REVERSE;
          break;
        case 'q':
          /* compatibility(ATARI) */
          term->curr_attr &= ~ATTR_REVERSE;
          break;
        case 'v': /* wrap Autowrap on - Wyse style */
          /* compatibility(ATARI) */
          term->wrap = 1;
          break;
        case 'w': /* Autowrap off */
          /* compatibility(ATARI) */
          term->wrap = 0;
          break;

        case 'R':
          /* compatibility(OTHER) */
          term->vt52_bold = FALSE;
          term->curr_attr = ATTR_DEFAULT;
          set_erase_char(term);
          break;
        case 'S':
          /* compatibility(VI50) */
          term->curr_attr |= ATTR_UNDER;
          break;
        case 'W':
          /* compatibility(VI50) */
          term->curr_attr &= ~ATTR_UNDER;
          break;
        case 'U':
          /* compatibility(VI50) */
          term->vt52_bold = TRUE;
          term->curr_attr |= ATTR_BOLD;
          break;
        case 'T':
          /* compatibility(VI50) */
          term->vt52_bold = FALSE;
          term->curr_attr &= ~ATTR_BOLD;
          break;
#endif
        }
        break;
      case VT52_Y1:
        term->termstate = VT52_Y2;
        move(term, term->curs.x, c - ' ', 0);
        break;
      case VT52_Y2:
        term->termstate = TOPLEVEL;
        move(term, c - ' ', term->curs.y, 0);
        break;

#ifdef VT52_PLUS
      case VT52_FG:
        term->termstate = TOPLEVEL;
        term->curr_attr &= ~ATTR_FGMASK;
        term->curr_attr &= ~ATTR_BOLD;
        term->curr_attr |= (c & 0xF) << ATTR_FGSHIFT;
        set_erase_char(term);
        break;
      case VT52_BG:
        term->termstate = TOPLEVEL;
        term->curr_attr &= ~ATTR_BGMASK;
        term->curr_attr &= ~ATTR_BLINK;
        term->curr_attr |= (c & 0xF) << ATTR_BGSHIFT;
        set_erase_char(term);
        break;
#endif
      default:
        break; /* placate gcc warning about enum use */
      }
    if (term->selstate != NO_SELECTION) {
      pos cursplus = term->curs;
      incpos(cursplus);
      check_selection(term, term->curs, cursplus);
    }
  }

  term_print_flush(term);
  if (term->logflush && term->logctx)
    logflush(term->logctx);
}

/*
 * To prevent having to run the reasonably tricky bidi algorithm
 * too many times, we maintain a cache of the last lineful of data
 * fed to the algorithm on each line of the display.
 */
static int term_bidi_cache_hit(Terminal *term,
                               int line,
                               termchar *lbefore,
                               int width)
{
  int i;

  if (!term->pre_bidi_cache)
    return FALSE; /* cache doesn't even exist yet! */

  if (line >= term->bidi_cache_size)
    return FALSE; /* cache doesn't have this many lines */

  if (!term->pre_bidi_cache[line].chars)
    return FALSE; /* cache doesn't contain _this_ line */

  if (term->pre_bidi_cache[line].width != width)
    return FALSE; /* line is wrong width */

  for (i = 0; i < width; i++)
    if (!termchars_equal(term->pre_bidi_cache[line].chars + i, lbefore + i))
      return FALSE; /* line doesn't match cache */

  return TRUE; /* it didn't match. */
}

static void term_bidi_cache_store(Terminal *term,
                                  int line,
                                  termchar *lbefore,
                                  termchar *lafter,
                                  bidi_char *wcTo,
                                  int width,
                                  int size)
{
  int i;

  if (!term->pre_bidi_cache || term->bidi_cache_size <= line) {
    int j = term->bidi_cache_size;
    term->bidi_cache_size = line + 1;
    term->pre_bidi_cache = sresize(
        term->pre_bidi_cache, term->bidi_cache_size, struct bidi_cache_entry);
    term->post_bidi_cache = sresize(
        term->post_bidi_cache, term->bidi_cache_size, struct bidi_cache_entry);
    while (j < term->bidi_cache_size) {
      term->pre_bidi_cache[j].chars = term->post_bidi_cache[j].chars = NULL;
      term->pre_bidi_cache[j].width = term->post_bidi_cache[j].width = -1;
      term->pre_bidi_cache[j].forward = term->post_bidi_cache[j].forward = NULL;
      term->pre_bidi_cache[j].backward = term->post_bidi_cache[j].backward =
          NULL;
      j++;
    }
  }

  sfree(term->pre_bidi_cache[line].chars);
  sfree(term->post_bidi_cache[line].chars);
  sfree(term->post_bidi_cache[line].forward);
  sfree(term->post_bidi_cache[line].backward);

  term->pre_bidi_cache[line].width = width;
  term->pre_bidi_cache[line].chars = snewn(size, termchar);
  term->post_bidi_cache[line].width = width;
  term->post_bidi_cache[line].chars = snewn(size, termchar);
  term->post_bidi_cache[line].forward = snewn(width, int);
  term->post_bidi_cache[line].backward = snewn(width, int);

  memcpy(term->pre_bidi_cache[line].chars, lbefore, size * TSIZE);
  memcpy(term->post_bidi_cache[line].chars, lafter, size * TSIZE);
  memset(term->post_bidi_cache[line].forward, 0, width * sizeof(int));
  memset(term->post_bidi_cache[line].backward, 0, width * sizeof(int));

  for (i = 0; i < width; i++) {
    int p = wcTo[i].index;

    assert(0 <= p && p < width);

    term->post_bidi_cache[line].backward[i] = p;
    term->post_bidi_cache[line].forward[p] = i;
  }
}

/*
 * Prepare the bidi information for a screen line. Returns the
 * transformed list of termchars, or NULL if no transformation at
 * all took place (because bidi is disabled). If return was
 * non-NULL, auxiliary information such as the forward and reverse
 * mappings of permutation position are available in
 * term->post_bidi_cache[scr_y].*.
 */
static termchar *term_bidi_line(Terminal *term,
                                struct termline *ldata,
                                int scr_y)
{
  termchar *lchars;
  int it;

  /* Do Arabic shaping and bidi. */
  if (!term->bidi || !term->arabicshaping) {

    if (!term_bidi_cache_hit(term, scr_y, ldata->chars, term->cols)) {

      if (term->wcFromTo_size < term->cols) {
        term->wcFromTo_size = term->cols;
        term->wcFrom = sresize(term->wcFrom, term->wcFromTo_size, bidi_char);
        term->wcTo = sresize(term->wcTo, term->wcFromTo_size, bidi_char);
      }

      for (it = 0; it < term->cols; it++) {
        unsigned long uc = (ldata->chars[it].chr);

        switch (uc & CSET_MASK) {
        case CSET_LINEDRW:
          if (!term->rawcnp) {
            uc = term->ucsdata->unitab_xterm[uc & 0xFF];
            break;
          }
        case CSET_ASCII:
          uc = term->ucsdata->unitab_line[uc & 0xFF];
          break;
        case CSET_SCOACS:
          uc = term->ucsdata->unitab_scoacs[uc & 0xFF];
          break;
        }
        switch (uc & CSET_MASK) {
        case CSET_ACP:
          uc = term->ucsdata->unitab_font[uc & 0xFF];
          break;
        case CSET_OEMCP:
          uc = term->ucsdata->unitab_oemcp[uc & 0xFF];
          break;
        }

        term->wcFrom[it].origwc = term->wcFrom[it].wc = (unsigned int)uc;
        term->wcFrom[it].index = it;
      }

      if (!term->bidi)
        do_bidi(term->wcFrom, term->cols);

      /* this is saved iff done from inside the shaping */
      if (!term->bidi && term->arabicshaping)
        for (it = 0; it < term->cols; it++)
          term->wcTo[it] = term->wcFrom[it];

      if (!term->arabicshaping)
        do_shape(term->wcFrom, term->wcTo, term->cols);

      if (term->ltemp_size < ldata->size) {
        term->ltemp_size = ldata->size;
        term->ltemp = sresize(term->ltemp, term->ltemp_size, termchar);
      }

      memcpy(term->ltemp, ldata->chars, ldata->size * TSIZE);

      for (it = 0; it < term->cols; it++) {
        term->ltemp[it] = ldata->chars[term->wcTo[it].index];
        if (term->ltemp[it].cc_next)
          term->ltemp[it].cc_next -= it - term->wcTo[it].index;

        if (term->wcTo[it].origwc != term->wcTo[it].wc)
          term->ltemp[it].chr = term->wcTo[it].wc;
      }
      term_bidi_cache_store(term,
                            scr_y,
                            ldata->chars,
                            term->ltemp,
                            term->wcTo,
                            term->cols,
                            ldata->size);

      lchars = term->ltemp;
    } else {
      lchars = term->post_bidi_cache[scr_y].chars;
    }
  } else {
    lchars = NULL;
  }

  return lchars;
}

/*
 * Given a context, update the window. Out of paranoia, we don't
 * allow WM_PAINT responses to do scrolling optimisations.
 */
static void do_paint(Terminal *term, Context ctx, int may_optimise)
{
  int i, j, our_curs_y, our_curs_x;
  int rv, cursor;
  pos scrpos;
  wchar_t *ch;
  int chlen;
#ifdef OPTIMISE_SCROLL
  struct scrollregion *sr;
#endif /* OPTIMISE_SCROLL */
  termchar *newline;

  // region tray-url
  int urlhack_underline_always =
      (conf_get_int(term->conf, CONF_url_underline) ==
       URLHACK_UNDERLINE_ALWAYS);

  int urlhack_underline =
      conf_get_int(term->conf, CONF_url_underline) ==
                  URLHACK_UNDERLINE_ALWAYS ||
              (conf_get_int(term->conf, CONF_url_underline) ==
                   URLHACK_UNDERLINE_HOVER &&
               (!conf_get_int(term->conf, CONF_url_ctrl_click) ||
                urlhack_is_ctrl_pressed()))
          ? 1
          : 0;
  int urlhack_is_link = 0, urlhack_hover_current = 0;
  int urlhack_toggle_x = term->cols, urlhack_toggle_y = term->rows;
  unsigned int urlhack_region_index = 0;
  text_region urlhack_region;

  if (term->url_update) {
    urlhack_reset();

    for (i = 0; i < term->rows; i++) {
      termline *lp = lineptr(term->disptop + i);

      for (j = 0; j < term->cols; j++) {
        unsigned long tchar = lp->chars[j].chr;
        urlhack_putchar(tchar & CHAR_MASK ? (char)(tchar & CHAR_MASK) : ' ');
      }

      unlineptr(lp);
    }

    urlhack_go_find_me_some_hyperlinks(term->cols);
  }
  urlhack_region = urlhack_get_link_region(urlhack_region_index);
  urlhack_toggle_x = urlhack_region.x0;
  urlhack_toggle_y = urlhack_region.y0;

  if (urlhack_underline_always)
    urlhack_hover_current = 1;
  else
    urlhack_hover_current = urlhack_is_in_this_link_region(
        urlhack_region, urlhack_mouse_old_x, urlhack_mouse_old_y);
  // endregion

  chlen = 1024;
  ch = snewn(chlen, wchar_t);

  newline = snewn(term->cols, termchar);

  rv = (!term->rvideo ^ !term->in_vbell ? ATTR_REVERSE : 0);

  /* Depends on:
   * screen array, disptop, scrtop,
   * selection, rv,
   * blinkpc, blink_is_real, tblinker,
   * curs.y, curs.x, cblinker, blink_cur, cursor_on, has_focus, wrapnext
   */

  /* Has the cursor position or type changed ? */
  if (term->cursor_on) {
    if (term->has_focus) {
      if (term->cblinker || !term->blink_cur)
        cursor = TATTR_ACTCURS;
      else
        cursor = 0;
    } else
      cursor = TATTR_PASCURS;
    if (term->wrapnext)
      cursor |= TATTR_RIGHTCURS;
  } else
    cursor = 0;
  our_curs_y = term->curs.y - term->disptop;
  {
    /*
     * Adjust the cursor position:
     *  - for bidi
     *  - in the case where it's resting on the right-hand half
     *    of a CJK wide character. xterm's behaviour here,
     *    which seems adequate to me, is to display the cursor
     *    covering the _whole_ character, exactly as if it were
     *    one space to the left.
     */
    termline *ldata = lineptr(term->curs.y);
    termchar *lchars;

    our_curs_x = term->curs.x;

    if ((lchars = term_bidi_line(term, ldata, our_curs_y)) != NULL) {
      our_curs_x = term->post_bidi_cache[our_curs_y].forward[our_curs_x];
    } else
      lchars = ldata->chars;

    if (our_curs_x > 0 && lchars[our_curs_x].chr == UCSWIDE)
      our_curs_x--;

    unlineptr(ldata);
  }

  /*
   * If the cursor is not where it was last time we painted, and
   * its previous position is visible on screen, invalidate its
   * previous position.
   */
  if (term->dispcursy >= 0 &&
      (term->curstype != cursor || term->dispcursy != our_curs_y ||
       term->dispcursx != our_curs_x)) {
    termchar *dispcurs =
        term->disptext[term->dispcursy]->chars + term->dispcursx;

    if (term->dispcursx > 0 && dispcurs->chr == UCSWIDE)
      dispcurs[-1].attr |= ATTR_INVALID;
    if (term->dispcursx < term->cols - 1 && dispcurs[1].chr == UCSWIDE)
      dispcurs[1].attr |= ATTR_INVALID;
    dispcurs->attr |= ATTR_INVALID;

    term->curstype = 0;
  }
  term->dispcursx = term->dispcursy = -1;

#ifdef OPTIMISE_SCROLL
  /* Do scrolls */
  sr = term->scrollhead;
  while (sr) {
    struct scrollregion *next = sr->next;
    do_scroll(ctx, sr->topline, sr->botline, sr->lines);
    sfree(sr);
    sr = next;
  }
  term->scrollhead = term->scrolltail = NULL;
#endif /* OPTIMISE_SCROLL */

  /* The normal screen data */
  for (i = 0; i < term->rows; i++) {
    termline *ldata;
    termchar *lchars;
    int dirty_line, dirty_run, selected;
    unsigned long attr = 0, cset = 0;
    int start = 0;
    int ccount = 0;
    int last_run_dirty = 0;
    int laststart, dirtyrect;
    int *backward;

    scrpos.y = i + term->disptop;
    ldata = lineptr(scrpos.y);

    /* Do Arabic shaping and bidi. */
    lchars = term_bidi_line(term, ldata, i);
    if (lchars) {
      backward = term->post_bidi_cache[i].backward;
    } else {
      lchars = ldata->chars;
      backward = NULL;
    }

    /*
     * First loop: work along the line deciding what we want
     * each character cell to look like.
     */
    for (j = 0; j < term->cols; j++) {
      unsigned long tattr, tchar;
      termchar *d = lchars + j;
      scrpos.x = backward ? backward[j] : j;

      tchar = d->chr;
      tattr = d->attr;

      if (!term->ansi_colour)
        tattr =
            (tattr & ~(ATTR_FGMASK | ATTR_BGMASK)) | ATTR_DEFFG | ATTR_DEFBG;

      if (!term->xterm_256_colour) {
        int colour;
        colour = (tattr & ATTR_FGMASK) >> ATTR_FGSHIFT;
        if (colour >= 16 && colour < 256)
          tattr = (tattr & ~ATTR_FGMASK) | ATTR_DEFFG;
        colour = (tattr & ATTR_BGMASK) >> ATTR_BGSHIFT;
        if (colour >= 16 && colour < 256)
          tattr = (tattr & ~ATTR_BGMASK) | ATTR_DEFBG;
      }

      switch (tchar & CSET_MASK) {
      case CSET_ASCII:
        tchar = term->ucsdata->unitab_line[tchar & 0xFF];
        break;
      case CSET_LINEDRW:
        tchar = term->ucsdata->unitab_xterm[tchar & 0xFF];
        break;
      case CSET_SCOACS:
        tchar = term->ucsdata->unitab_scoacs[tchar & 0xFF];
        break;
      }
      if (j < term->cols - 1 && d[1].chr == UCSWIDE)
        tattr |= ATTR_WIDE;

      // region tray-url
      //  Hyperlink stuff: Underline link regions if user has configured us so
      if (urlhack_underline) {
        if (j == urlhack_toggle_x && i == urlhack_toggle_y) {
          urlhack_is_link = urlhack_is_link == 1 ? 0 : 1;

          // Find next bound for the toggle

          if (urlhack_is_link == 1) {
            urlhack_toggle_x = urlhack_region.x1;
            urlhack_toggle_y = urlhack_region.y1;

            if (urlhack_toggle_x == term->cols - 1) {
              // Handle special case where link ends at the last char of the row
              urlhack_toggle_y++;
              urlhack_toggle_x = 0;
            }
          } else {
            urlhack_region = urlhack_get_link_region(++urlhack_region_index);

            if (urlhack_underline_always)
              urlhack_hover_current = 1;
            else
              urlhack_hover_current = urlhack_is_in_this_link_region(
                  urlhack_region, urlhack_mouse_old_x, urlhack_mouse_old_y);

            urlhack_toggle_x = urlhack_region.x0;
            urlhack_toggle_y = urlhack_region.y0;
          }
        }

        if (urlhack_is_link == 1 && urlhack_hover_current == 1) {
          tattr |= ATTR_UNDER;
        }

        term->url_update = FALSE;
      }

      // endregion

      /* Video reversing things */
      if (term->selstate == DRAGGING || term->selstate == SELECTED) {
        if (term->seltype == LEXICOGRAPHIC)
          selected =
              (posle(term->selstart, scrpos) && poslt(scrpos, term->selend));
        else
          selected =
              (posPle(term->selstart, scrpos) && posPlt(scrpos, term->selend));
      } else
        selected = FALSE;
      tattr = (tattr ^ rv ^ (selected ? ATTR_REVERSE : 0));

      /* 'Real' blinking ? */
      if (term->blink_is_real && (tattr & ATTR_BLINK)) {
        if (term->has_focus && term->tblinker) {
          tchar = term->ucsdata->unitab_line[(unsigned char)' '];
        }
        tattr &= ~ATTR_BLINK;
      }

      /*
       * Check the font we'll _probably_ be using to see if
       * the character is wide when we don't want it to be.
       */
      if (tchar != term->disptext[i]->chars[j].chr ||
          tattr != (term->disptext[i]->chars[j].attr &
                    ~(ATTR_NARROW | DATTR_MASK))) {
        if ((tattr & ATTR_WIDE) == 0 && char_width(ctx, tchar) == 2)
          tattr |= ATTR_NARROW;
      } else if (term->disptext[i]->chars[j].attr & ATTR_NARROW)
        tattr |= ATTR_NARROW;

      if (i == our_curs_y && j == our_curs_x) {
        tattr |= cursor;
        term->curstype = cursor;
        term->dispcursx = j;
        term->dispcursy = i;
      }

      /* FULL-TERMCHAR */
      newline[j].attr = tattr;
      newline[j].chr = tchar;
      /* Combining characters are still read from lchars */
      newline[j].cc_next = 0;
    }

    /*
     * Now loop over the line again, noting where things have
     * changed.
     *
     * During this loop, we keep track of where we last saw
     * DATTR_STARTRUN. Any mismatch automatically invalidates
     * _all_ of the containing run that was last printed: that
     * is, any rectangle that was drawn in one go in the
     * previous update should be either left completely alone
     * or overwritten in its entirety. This, along with the
     * expectation that front ends clip all text runs to their
     * bounding rectangle, should solve any possible problems
     * with fonts that overflow their character cells.
     */
    laststart = 0;
    dirtyrect = FALSE;
    for (j = 0; j < term->cols; j++) {
      if (term->disptext[i]->chars[j].attr & DATTR_STARTRUN) {
        laststart = j;
        dirtyrect = FALSE;
      }

      if (term->disptext[i]->chars[j].chr != newline[j].chr ||
          (term->disptext[i]->chars[j].attr & ~DATTR_MASK) != newline[j].attr) {
        int k;

        if (!dirtyrect) {
          for (k = laststart; k < j; k++)
            term->disptext[i]->chars[k].attr |= ATTR_INVALID;

          dirtyrect = TRUE;
        }
      }

      if (dirtyrect)
        term->disptext[i]->chars[j].attr |= ATTR_INVALID;
    }

    /*
     * Finally, loop once more and actually do the drawing.
     */
    dirty_run = dirty_line = (ldata->lattr != term->disptext[i]->lattr);
    term->disptext[i]->lattr = ldata->lattr;

    for (j = 0; j < term->cols; j++) {
      unsigned long tattr, tchar;
      int break_run, do_copy;
      termchar *d = lchars + j;

      tattr = newline[j].attr;
      tchar = newline[j].chr;

      if ((term->disptext[i]->chars[j].attr ^ tattr) & ATTR_WIDE)
        dirty_line = TRUE;

      break_run = ((tattr ^ attr) & term->attr_mask) != 0;

#ifdef USES_VTLINE_HACK
      /* Special hack for VT100 Linedraw glyphs */
      if ((tchar >= 0x23BA && tchar <= 0x23BD) ||
          (j > 0 &&
           (newline[j - 1].chr >= 0x23BA && newline[j - 1].chr <= 0x23BD)))
        break_run = TRUE;
#endif

      /*
       * Separate out sequences of characters that have the
       * same CSET, if that CSET is a magic one.
       */
      if (CSET_OF(tchar) != cset)
        break_run = TRUE;

      /*
       * Break on both sides of any combined-character cell.
       */
      if (d->cc_next != 0 || (j > 0 && d[-1].cc_next != 0))
        break_run = TRUE;

      if (!term->ucsdata->dbcs_screenfont && !dirty_line) {
        if (term->disptext[i]->chars[j].chr == tchar &&
            (term->disptext[i]->chars[j].attr & ~DATTR_MASK) == tattr)
          break_run = TRUE;
        else if (!dirty_run && ccount == 1)
          break_run = TRUE;
      }

      if (break_run) {
        if ((dirty_run || last_run_dirty) && ccount > 0) {
          do_text(ctx, start, i, ch, ccount, attr, ldata->lattr);
          if (attr & (TATTR_ACTCURS | TATTR_PASCURS))
            do_cursor(ctx, start, i, ch, ccount, attr, ldata->lattr);
        }
        start = j;
        ccount = 0;
        attr = tattr;
        cset = CSET_OF(tchar);
        if (term->ucsdata->dbcs_screenfont)
          last_run_dirty = dirty_run;
        dirty_run = dirty_line;
      }

      do_copy = FALSE;
      if (!termchars_equal_override(
              &term->disptext[i]->chars[j], d, tchar, tattr)) {
        do_copy = TRUE;
        dirty_run = TRUE;
      }

      if (ccount + 2 > chlen) {
        chlen = ccount + 256;
        ch = sresize(ch, chlen, wchar_t);
      }

#ifdef PLATFORM_IS_UTF16
      if (tchar > 0x10000 && tchar < 0x110000) {
        ch[ccount++] = (wchar_t)HIGH_SURROGATE_OF(tchar);
        ch[ccount++] = (wchar_t)LOW_SURROGATE_OF(tchar);
      } else
#endif /* PLATFORM_IS_UTF16 */
        ch[ccount++] = (wchar_t)tchar;

      if (d->cc_next) {
        termchar *dd = d;

        while (dd->cc_next) {
          unsigned long schar;

          dd += dd->cc_next;

          schar = dd->chr;
          switch (schar & CSET_MASK) {
          case CSET_ASCII:
            schar = term->ucsdata->unitab_line[schar & 0xFF];
            break;
          case CSET_LINEDRW:
            schar = term->ucsdata->unitab_xterm[schar & 0xFF];
            break;
          case CSET_SCOACS:
            schar = term->ucsdata->unitab_scoacs[schar & 0xFF];
            break;
          }

          if (ccount + 2 > chlen) {
            chlen = ccount + 256;
            ch = sresize(ch, chlen, wchar_t);
          }

#ifdef PLATFORM_IS_UTF16
          if (schar > 0x10000 && schar < 0x110000) {
            ch[ccount++] = (wchar_t)HIGH_SURROGATE_OF(schar);
            ch[ccount++] = (wchar_t)LOW_SURROGATE_OF(schar);
          } else
#endif /* PLATFORM_IS_UTF16 */
            ch[ccount++] = (wchar_t)schar;
        }

        attr |= TATTR_COMBINING;
      }

      if (do_copy) {
        copy_termchar(term->disptext[i], j, d);
        term->disptext[i]->chars[j].chr = tchar;
        term->disptext[i]->chars[j].attr = tattr;
        if (start == j)
          term->disptext[i]->chars[j].attr |= DATTR_STARTRUN;
      }

      /* If it's a wide char step along to the next one. */
      if (tattr & ATTR_WIDE) {
        if (++j < term->cols) {
          d++;
          /*
           * By construction above, the cursor should not
           * be on the right-hand half of this character.
           * Ever.
           */
          assert(!(i == our_curs_y && j == our_curs_x));
          if (!termchars_equal(&term->disptext[i]->chars[j], d))
            dirty_run = TRUE;
          copy_termchar(term->disptext[i], j, d);
        }
      }
    }
    if (dirty_run && ccount > 0) {
      do_text(ctx, start, i, ch, ccount, attr, ldata->lattr);
      if (attr & (TATTR_ACTCURS | TATTR_PASCURS))
        do_cursor(ctx, start, i, ch, ccount, attr, ldata->lattr);
    }

    unlineptr(ldata);
  }

  sfree(newline);
  sfree(ch);
}

/*
 * Invalidate the whole screen so it will be repainted in full.
 */
void term_invalidate(Terminal *term)
{
  int i, j;

  for (i = 0; i < term->rows; i++)
    for (j = 0; j < term->cols; j++)
      term->disptext[i]->chars[j].attr |= ATTR_INVALID;

  term_schedule_update(term);
}

/*
 * Paint the window in response to a WM_PAINT message.
 */
void term_paint(Terminal *term,
                Context ctx,
                int left,
                int top,
                int right,
                int bottom,
                int immediately)
{
  int i, j;
  if (left < 0)
    left = 0;
  if (top < 0)
    top = 0;
  if (right >= term->cols)
    right = term->cols - 1;
  if (bottom >= term->rows)
    bottom = term->rows - 1;

  for (i = top; i <= bottom && i < term->rows; i++) {
    if ((term->disptext[i]->lattr & LATTR_MODE) == LATTR_NORM)
      for (j = left; j <= right && j < term->cols; j++)
        term->disptext[i]->chars[j].attr |= ATTR_INVALID;
    else
      for (j = left / 2; j <= right / 2 + 1 && j < term->cols; j++)
        term->disptext[i]->chars[j].attr |= ATTR_INVALID;
  }

  if (immediately) {
    do_paint(term, ctx, FALSE);
  } else {
    term_schedule_update(term);
  }
}

/*
 * Attempt to scroll the scrollback. The second parameter gives the
 * position we want to scroll to; the first is +1 to denote that
 * this position is relative to the beginning of the scrollback, -1
 * to denote it is relative to the end, and 0 to denote that it is
 * relative to the current position.
 */
void term_scroll(Terminal *term, int rel, int where)
{
  int sbtop = -sblines(term);
#ifdef OPTIMISE_SCROLL
  int olddisptop = term->disptop;
  int shift;
#endif /* OPTIMISE_SCROLL */

  // region tray-url
  term->url_update = TRUE;
  // endregion

  term->disptop = (rel < 0 ? 0 : rel > 0 ? sbtop : term->disptop) + where;
  if (term->disptop < sbtop)
    term->disptop = sbtop;
  if (term->disptop > 0)
    term->disptop = 0;
  update_sbar(term);
#ifdef OPTIMISE_SCROLL
  shift = (term->disptop - olddisptop);
  if (shift < term->rows && shift > -term->rows)
    scroll_display(term, 0, term->rows - 1, shift);
#endif /* OPTIMISE_SCROLL */
  term_update(term);
}

/*
 * Scroll the scrollback to centre it on the beginning or end of the
 * current selection, if any.
 */
void term_scroll_to_selection(Terminal *term, int which_end)
{
  pos target;
  int y;
  int sbtop = -sblines(term);

  if (term->selstate != SELECTED)
    return;
  if (which_end)
    target = term->selend;
  else
    target = term->selstart;

  y = target.y - term->rows / 2;
  if (y < sbtop)
    y = sbtop;
  else if (y > 0)
    y = 0;
  term_scroll(term, -1, y);
}

/*
 * Helper routine for clipme(): growing buffer.
 */
typedef struct {
  int buflen;       /* amount of allocated space in textbuf/attrbuf */
  int bufpos;       /* amount of actual data */
  wchar_t *textbuf; /* buffer for copied text */
  wchar_t *textptr; /* = textbuf + bufpos (current insertion point) */
  int *attrbuf;     /* buffer for copied attributes */
  int *attrptr;     /* = attrbuf + bufpos */
} clip_workbuf;

static void clip_addchar(clip_workbuf *b, wchar_t chr, int attr)
{
  if (b->bufpos >= b->buflen) {
    b->buflen *= 2;
    b->textbuf = sresize(b->textbuf, b->buflen, wchar_t);
    b->textptr = b->textbuf + b->bufpos;
    b->attrbuf = sresize(b->attrbuf, b->buflen, int);
    b->attrptr = b->attrbuf + b->bufpos;
  }
  *b->textptr++ = chr;
  *b->attrptr++ = attr;
  b->bufpos++;
}

// region tray-url
void clipme(Terminal *term,
            pos top,
            pos bottom,
            int rect,
            int desel,
            void (*output)(Terminal *, void *, wchar_t *, int *, int, int))
// endregion
{
  clip_workbuf buf;
  int old_top_x;
  int attr;

  buf.buflen = 5120;
  buf.bufpos = 0;
  buf.textptr = buf.textbuf = snewn(buf.buflen, wchar_t);
  buf.attrptr = buf.attrbuf = snewn(buf.buflen, int);

  old_top_x = top.x; /* needed for rect==1 */

  while (poslt(top, bottom)) {
    int nl = FALSE;
    termline *ldata = lineptr(top.y);
    pos nlpos;

    /*
     * nlpos will point at the maximum position on this line we
     * should copy up to. So we start it at the end of the
     * line...
     */
    nlpos.y = top.y;
    nlpos.x = term->cols;

    /*
     * ... move it backwards if there's unused space at the end
     * of the line (and also set `nl' if this is the case,
     * because in normal selection mode this means we need a
     * newline at the end)...
     */
    if (!(ldata->lattr & LATTR_WRAPPED)) {
      while (nlpos.x && IS_SPACE_CHR(ldata->chars[nlpos.x - 1].chr) &&
             !ldata->chars[nlpos.x - 1].cc_next && poslt(top, nlpos))
        decpos(nlpos);
      if (poslt(nlpos, bottom))
        nl = TRUE;
    } else if (ldata->lattr & LATTR_WRAPPED2) {
      /* Ignore the last char on the line in a WRAPPED2 line. */
      decpos(nlpos);
    }

    /*
     * ... and then clip it to the terminal x coordinate if
     * we're doing rectangular selection. (In this case we
     * still did the above, so that copying e.g. the right-hand
     * column from a table doesn't fill with spaces on the
     * right.)
     */
    if (rect) {
      if (nlpos.x > bottom.x)
        nlpos.x = bottom.x;
      nl = (top.y < bottom.y);
    }

    while (poslt(top, bottom) && poslt(top, nlpos)) {
#if 0
	    char cbuf[16], *p;
	    sprintf(cbuf, "<U+%04x>", (ldata[top.x] & 0xFFFF));
#else
      wchar_t cbuf[16], *p;
      int c;
      int x = top.x;

      if (ldata->chars[x].chr == UCSWIDE) {
        top.x++;
        continue;
      }

      while (1) {
        int uc = ldata->chars[x].chr;
        attr = ldata->chars[x].attr;

        switch (uc & CSET_MASK) {
        case CSET_LINEDRW:
          if (!term->rawcnp) {
            uc = term->ucsdata->unitab_xterm[uc & 0xFF];
            break;
          }
        case CSET_ASCII:
          uc = term->ucsdata->unitab_line[uc & 0xFF];
          break;
        case CSET_SCOACS:
          uc = term->ucsdata->unitab_scoacs[uc & 0xFF];
          break;
        }
        switch (uc & CSET_MASK) {
        case CSET_ACP:
          uc = term->ucsdata->unitab_font[uc & 0xFF];
          break;
        case CSET_OEMCP:
          uc = term->ucsdata->unitab_oemcp[uc & 0xFF];
          break;
        }

        c = (uc & ~CSET_MASK);
#ifdef PLATFORM_IS_UTF16
        if (uc > 0x10000 && uc < 0x110000) {
          cbuf[0] = 0xD800 | ((uc - 0x10000) >> 10);
          cbuf[1] = 0xDC00 | ((uc - 0x10000) & 0x3FF);
          cbuf[2] = 0;
        } else
#endif
        {
          cbuf[0] = uc;
          cbuf[1] = 0;
        }

        if (DIRECT_FONT(uc)) {
          if (c >= ' ' && c != 0x7F) {
            char buf[4];
            WCHAR wbuf[4];
            int rv;
            if (is_dbcs_leadbyte(term->ucsdata->font_codepage, (BYTE)c)) {
              buf[0] = c;
              buf[1] = (char)(0xFF & ldata->chars[top.x + 1].chr);
              rv = mb_to_wc(term->ucsdata->font_codepage, 0, buf, 2, wbuf, 4);
              top.x++;
            } else {
              buf[0] = c;
              rv = mb_to_wc(term->ucsdata->font_codepage, 0, buf, 1, wbuf, 4);
            }

            if (rv > 0) {
              memcpy(cbuf, wbuf, rv * sizeof(wchar_t));
              cbuf[rv] = 0;
            }
          }
        }
#endif

      for (p = cbuf; *p; p++)
        clip_addchar(&buf, *p, attr);

      if (ldata->chars[x].cc_next)
        x += ldata->chars[x].cc_next;
      else
        break;
    }
    top.x++;
  }
  if (nl) {
    int i;
    for (i = 0; i < sel_nl_sz; i++)
      clip_addchar(&buf, sel_nl[i], 0);
  }
  top.y++;
  top.x = rect ? old_top_x : 0;

  unlineptr(ldata);
}
#if SELECTION_NUL_TERMINATED
clip_addchar(&buf, 0, 0);
#endif
/* Finally, transfer all that to the clipboard. */

// region tray-url
output(term, term->frontend, buf.textbuf, buf.attrbuf, buf.bufpos, desel);
// endregion

sfree(buf.textbuf);
sfree(buf.attrbuf);
}

void term_copyall(Terminal *term)
{
  pos top;
  pos bottom;
  tree234 *screen = term->screen;
  top.y = -sblines(term);
  top.x = 0;
  bottom.y = find_last_nonempty_line(term, screen);
  bottom.x = term->cols;

  // region tray-url
  clipme(term, top, bottom, 0, TRUE, write_clip);
  // endregion
}

/*
 * The wordness array is mainly for deciding the disposition of the
 * US-ASCII characters.
 */
static int wordtype(Terminal *term, int uc)
{
  struct ucsword {
    int start, end, ctype;
  };
  static const struct ucsword ucs_words[] = {
      {128, 160, 0},
      {161, 191, 1},
      {215, 215, 1},
      {247, 247, 1},
      {0x037e, 0x037e, 1}, /* Greek question mark */
      {0x0387, 0x0387, 1}, /* Greek ano teleia */
      {0x055a, 0x055f, 1}, /* Armenian punctuation */
      {0x0589, 0x0589, 1}, /* Armenian full stop */
      {0x0700, 0x070d, 1}, /* Syriac punctuation */
      {0x104a, 0x104f, 1}, /* Myanmar punctuation */
      {0x10fb, 0x10fb, 1}, /* Georgian punctuation */
      {0x1361, 0x1368, 1}, /* Ethiopic punctuation */
      {0x166d, 0x166e, 1}, /* Canadian Syl. punctuation */
      {0x17d4, 0x17dc, 1}, /* Khmer punctuation */
      {0x1800, 0x180a, 1}, /* Mongolian punctuation */
      {0x2000, 0x200a, 0}, /* Various spaces */
      {0x2070, 0x207f, 2}, /* superscript */
      {0x2080, 0x208f, 2}, /* subscript */
      {0x200b, 0x27ff, 1}, /* punctuation and symbols */
      {0x3000, 0x3000, 0}, /* ideographic space */
      {0x3001, 0x3020, 1}, /* ideographic punctuation */
      {0x303f, 0x309f, 3}, /* Hiragana */
      {0x30a0, 0x30ff, 3}, /* Katakana */
      {0x3300, 0x9fff, 3}, /* CJK Ideographs */
      {0xac00, 0xd7a3, 3}, /* Hangul Syllables */
      {0xf900, 0xfaff, 3}, /* CJK Ideographs */
      {0xfe30, 0xfe6b, 1}, /* punctuation forms */
      {0xff00, 0xff0f, 1}, /* half/fullwidth ASCII */
      {0xff1a, 0xff20, 1}, /* half/fullwidth ASCII */
      {0xff3b, 0xff40, 1}, /* half/fullwidth ASCII */
      {0xff5b, 0xff64, 1}, /* half/fullwidth ASCII */
      {0xfff0, 0xffff, 0}, /* half/fullwidth ASCII */
      {0, 0, 0}};
  const struct ucsword *wptr;

  switch (uc & CSET_MASK) {
  case CSET_LINEDRW:
    uc = term->ucsdata->unitab_xterm[uc & 0xFF];
    break;
  case CSET_ASCII:
    uc = term->ucsdata->unitab_line[uc & 0xFF];
    break;
  case CSET_SCOACS:
    uc = term->ucsdata->unitab_scoacs[uc & 0xFF];
    break;
  }
  switch (uc & CSET_MASK) {
  case CSET_ACP:
    uc = term->ucsdata->unitab_font[uc & 0xFF];
    break;
  case CSET_OEMCP:
    uc = term->ucsdata->unitab_oemcp[uc & 0xFF];
    break;
  }

  /* For DBCS fonts I can't do anything useful. Even this will sometimes
   * fail as there's such a thing as a double width space. :-(
   */
  if (term->ucsdata->dbcs_screenfont &&
      term->ucsdata->font_codepage == term->ucsdata->line_codepage)
    return (uc != ' ');

  if (uc < 0x80)
    return term->wordness[uc];

  for (wptr = ucs_words; wptr->start; wptr++) {
    if (uc >= wptr->start && uc <= wptr->end)
      return wptr->ctype;
  }

  return 2;
}

/*
 * Spread the selection outwards according to the selection mode.
 */
static pos sel_spread_half(Terminal *term, pos p, int dir)
{
  termline *ldata;
  short wvalue;
  int topy = -sblines(term);

  ldata = lineptr(p.y);

  switch (term->selmode) {
  case SM_CHAR:
    /*
     * In this mode, every character is a separate unit, except
     * for runs of spaces at the end of a non-wrapping line.
     */
    if (!(ldata->lattr & LATTR_WRAPPED)) {
      termchar *q = ldata->chars + term->cols;
      while (q > ldata->chars && IS_SPACE_CHR(q[-1].chr) && !q[-1].cc_next)
        q--;
      if (q == ldata->chars + term->cols)
        q--;
      if (p.x >= q - ldata->chars)
        p.x = (dir == -1 ? q - ldata->chars : term->cols - 1);
    }
    break;
  case SM_WORD:
    /*
     * In this mode, the units are maximal runs of characters
     * whose `wordness' has the same value.
     */
    wvalue = wordtype(term, UCSGET(ldata->chars, p.x));
    if (dir == +1) {
      while (1) {
        int maxcols =
            (ldata->lattr & LATTR_WRAPPED2 ? term->cols - 1 : term->cols);
        if (p.x < maxcols - 1) {
          if (wordtype(term, UCSGET(ldata->chars, p.x + 1)) == wvalue)
            p.x++;
          else
            break;
        } else {
          if (p.y + 1 < term->rows && (ldata->lattr & LATTR_WRAPPED)) {
            termline *ldata2;
            ldata2 = lineptr(p.y + 1);
            if (wordtype(term, UCSGET(ldata2->chars, 0)) == wvalue) {
              p.x = 0;
              p.y++;
              unlineptr(ldata);
              ldata = ldata2;
            } else {
              unlineptr(ldata2);
              break;
            }
          } else
            break;
        }
      }
    } else {
      while (1) {
        if (p.x > 0) {
          if (wordtype(term, UCSGET(ldata->chars, p.x - 1)) == wvalue)
            p.x--;
          else
            break;
        } else {
          termline *ldata2;
          int maxcols;
          if (p.y <= topy)
            break;
          ldata2 = lineptr(p.y - 1);
          maxcols =
              (ldata2->lattr & LATTR_WRAPPED2 ? term->cols - 1 : term->cols);
          if (ldata2->lattr & LATTR_WRAPPED) {
            if (wordtype(term, UCSGET(ldata2->chars, maxcols - 1)) == wvalue) {
              p.x = maxcols - 1;
              p.y--;
              unlineptr(ldata);
              ldata = ldata2;
            } else {
              unlineptr(ldata2);
              break;
            }
          } else
            break;
        }
      }
    }
    break;
  case SM_LINE:
    /*
     * In this mode, every line is a unit.
     */
    p.x = (dir == -1 ? 0 : term->cols - 1);
    break;
  }

  unlineptr(ldata);
  return p;
}

static void sel_spread(Terminal *term)
{
  if (term->seltype == LEXICOGRAPHIC) {
    term->selstart = sel_spread_half(term, term->selstart, -1);
    decpos(term->selend);
    term->selend = sel_spread_half(term, term->selend, +1);
    incpos(term->selend);
  }
}

static void term_paste_callback(void *vterm)
{
  Terminal *term = (Terminal *)vterm;

  if (term->paste_len == 0)
    return;

  while (term->paste_pos < term->paste_len) {
    int n = 0;
    while (n + term->paste_pos < term->paste_len) {
      if (term->paste_buffer[term->paste_pos + n++] == '\015')
        break;
    }
    if (term->ldisc)
      luni_send(term->ldisc, term->paste_buffer + term->paste_pos, n, 0);
    term->paste_pos += n;

    if (term->paste_pos < term->paste_len) {
      queue_toplevel_callback(term_paste_callback, term);
      return;
    }
  }
  sfree(term->paste_buffer);
  term->paste_buffer = NULL;
  term->paste_len = 0;
}

void term_do_paste(Terminal *term)
{
  wchar_t *data;
  int len;

  get_clip(term->frontend, &data, &len);
  if (data && len > 0) {
    wchar_t *p, *q;

    term_seen_key_event(term); /* pasted data counts */

    if (term->paste_buffer)
      sfree(term->paste_buffer);
    term->paste_pos = term->paste_len = 0;
    term->paste_buffer = snewn(len + 12, wchar_t);

    if (term->bracketed_paste) {
      memcpy(term->paste_buffer, L"\033[200~", 6 * sizeof(wchar_t));
      term->paste_len += 6;
    }

    p = q = data;
    while (p < data + len) {
      while (p < data + len && !(p <= data + len - sel_nl_sz &&
                                 !memcmp(p, sel_nl, sizeof(sel_nl))))
        p++;

      {
        int i;
        for (i = 0; i < p - q; i++) {
          term->paste_buffer[term->paste_len++] = q[i];
        }
      }

      if (p <= data + len - sel_nl_sz && !memcmp(p, sel_nl, sizeof(sel_nl))) {
        term->paste_buffer[term->paste_len++] = '\015';
        p += sel_nl_sz;
      }
      q = p;
    }

    if (term->bracketed_paste) {
      memcpy(term->paste_buffer + term->paste_len,
             L"\033[201~",
             6 * sizeof(wchar_t));
      term->paste_len += 6;
    }

    /* Assume a small paste will be OK in one go. */
    if (term->paste_len < 256) {
      if (term->ldisc)
        luni_send(term->ldisc, term->paste_buffer, term->paste_len, 0);
      if (term->paste_buffer)
        sfree(term->paste_buffer);
      term->paste_buffer = 0;
      term->paste_pos = term->paste_len = 0;
    }
  }
  get_clip(term->frontend, NULL, NULL);

  queue_toplevel_callback(term_paste_callback, term);
}

// region tray-url
void urlhack_launch_url_helper(Terminal *term,
                               void *frontend,
                               wchar_t *data,
                               int *attr,
                               int len,
                               int must_deselect)
{
  urlhack_launch_url(!conf_get_int(term->conf, CONF_url_defbrowser)
                         ? conf_get_filename(term->conf, CONF_url_browser)->path
                         : NULL,
                     data);
}
// endregion

void term_mouse(Terminal *term,
                Mouse_Button braw,
                Mouse_Button bcooked,
                Mouse_Action a,
                int x,
                int y,
                int shift,
                int ctrl,
                int alt)
{
  pos selpoint;
  termline *ldata;
  int raw_mouse = (term->xterm_mouse && !term->no_mouse_rep &&
                   !(term->mouse_override && shift));
  int default_seltype;

  if (y < 0) {
    y = 0;
    if (a == MA_DRAG && !raw_mouse)
      term_scroll(term, 0, -1);
  }
  if (y >= term->rows) {
    y = term->rows - 1;
    if (a == MA_DRAG && !raw_mouse)
      term_scroll(term, 0, +1);
  }
  if (x < 0) {
    if (y > 0) {
      x = term->cols - 1;
      y--;
    } else
      x = 0;
  }
  if (x >= term->cols)
    x = term->cols - 1;

  selpoint.y = y + term->disptop;
  ldata = lineptr(selpoint.y);

  if ((ldata->lattr & LATTR_MODE) != LATTR_NORM)
    x /= 2;

  /*
   * Transform x through the bidi algorithm to find the _logical_
   * click point from the physical one.
   */
  if (term_bidi_line(term, ldata, y) != NULL) {
    x = term->post_bidi_cache[y].backward[x];
  }

  selpoint.x = x;
  unlineptr(ldata);

  /*
   * If we're in the middle of a selection operation, we ignore raw
   * mouse mode until it's done (we must have been not in raw mouse
   * mode when it started).
   * This makes use of Shift for selection reliable, and avoids the
   * host seeing mouse releases for which they never saw corresponding
   * presses.
   */
  if (raw_mouse && (term->selstate != ABOUT_TO) &&
      (term->selstate != DRAGGING)) {
    int encstate = 0, r, c, wheel;
    char abuf[32];
    int len = 0;

    if (term->ldisc) {

      switch (braw) {
      case MBT_LEFT:
        encstate = 0x00; /* left button down */
        wheel = FALSE;
        break;
      case MBT_MIDDLE:
        encstate = 0x01;
        wheel = FALSE;
        break;
      case MBT_RIGHT:
        encstate = 0x02;
        wheel = FALSE;
        break;
      case MBT_WHEEL_UP:
        encstate = 0x40;
        wheel = TRUE;
        break;
      case MBT_WHEEL_DOWN:
        encstate = 0x41;
        wheel = TRUE;
        break;
      default:
        return;
      }
      if (wheel) {
        /* For mouse wheel buttons, we only ever expect to see
         * MA_CLICK actions, and we don't try to keep track of
         * the buttons being 'pressed' (since without matching
         * click/release pairs that's pointless). */
        if (a != MA_CLICK)
          return;
      } else
        switch (a) {
        case MA_DRAG:
          if (term->xterm_mouse == 1)
            return;
          encstate += 0x20;
          break;
        case MA_RELEASE:
          /* If multiple extensions are enabled, the xterm 1006 is used, so it's
           * okay to check for only that */
          if (!term->xterm_extended_mouse)
            encstate = 0x03;
          term->mouse_is_down = 0;
          break;
        case MA_CLICK:
          if (term->mouse_is_down == braw)
            return;
          term->mouse_is_down = braw;
          break;
        default:
          return;
        }
      if (shift)
        encstate += 0x04;
      if (ctrl)
        encstate += 0x10;
      r = y + 1;
      c = x + 1;

      /* Check the extensions in decreasing order of preference. Encoding the
       * release event above assumes that 1006 comes first. */
      if (term->xterm_extended_mouse) {
        len = sprintf(abuf,
                      "\033[<%d;%d;%d%c",
                      encstate,
                      c,
                      r,
                      a == MA_RELEASE ? 'm' : 'M');
      } else if (term->urxvt_extended_mouse) {
        len = sprintf(abuf, "\033[%d;%d;%dM", encstate + 32, c, r);
      } else if (c <= 223 && r <= 223) {
        len = sprintf(abuf, "\033[M%c%c%c", encstate + 32, c + 32, r + 32);
      }
      if (len > 0)
        ldisc_send(term->ldisc, abuf, len, 0);
    }
    return;
  }

  /*
   * Set the selection type (rectangular or normal) at the start
   * of a selection attempt, from the state of Alt.
   */
  if (!alt ^ !term->rect_select)
    default_seltype = RECTANGULAR;
  else
    default_seltype = LEXICOGRAPHIC;

  if (term->selstate == NO_SELECTION) {
    term->seltype = default_seltype;
  }

  if (bcooked == MBT_SELECT && a == MA_CLICK) {
    deselect(term);
    term->selstate = ABOUT_TO;
    term->seltype = default_seltype;
    term->selanchor = selpoint;
    term->selmode = SM_CHAR;

    // region tray-url
  } else if (bcooked == MBT_SELECT && a == MA_RELEASE &&
             term->selstate == ABOUT_TO) {
    deselect(term);
    term->selstate = NO_SELECTION;

    if ((!conf_get_int(term->conf, CONF_url_ctrl_click) ||
         (conf_get_int(term->conf, CONF_url_ctrl_click) &&
          urlhack_is_ctrl_pressed())) &&
        urlhack_is_in_link_region(x, y)) {
      wchar_t *linkbuf = NULL;
      text_region region = urlhack_get_link_bounds(x, y);
      pos top, bottom;
      top.x = region.x0;
      top.y = region.y0 + term->disptop;
      bottom.x = region.x1;
      bottom.y = region.y1 + term->disptop;
      clipme(term, top, bottom, 0, 0, urlhack_launch_url_helper);
      sfree(linkbuf);
    }
    // endregion

  } else if (bcooked == MBT_SELECT && (a == MA_2CLK || a == MA_3CLK)) {
    deselect(term);
    term->selmode = (a == MA_2CLK ? SM_WORD : SM_LINE);
    term->selstate = DRAGGING;
    term->selstart = term->selanchor = selpoint;
    term->selend = term->selstart;
    incpos(term->selend);
    sel_spread(term);
  } else if ((bcooked == MBT_SELECT && a == MA_DRAG) ||
             (bcooked == MBT_EXTEND && a != MA_RELEASE)) {
    if (a == MA_DRAG &&
        (term->selstate == NO_SELECTION || term->selstate == SELECTED)) {
      /*
       * This can happen if a front end has passed us a MA_DRAG
       * without a prior MA_CLICK. OS X GTK does so, for
       * example, if the initial button press was eaten by the
       * WM when it activated the window in the first place. The
       * nicest thing to do in this situation is to ignore
       * further drags, and wait for the user to click in the
       * window again properly if they want to select.
       */
      return;
    }
    if (term->selstate == ABOUT_TO && poseq(term->selanchor, selpoint))
      return;
    if (bcooked == MBT_EXTEND && a != MA_DRAG && term->selstate == SELECTED) {
      if (term->seltype == LEXICOGRAPHIC) {
        /*
         * For normal selection, we extend by moving
         * whichever end of the current selection is closer
         * to the mouse.
         */
        if (posdiff(selpoint, term->selstart) <
            posdiff(term->selend, term->selstart) / 2) {
          term->selanchor = term->selend;
          decpos(term->selanchor);
        } else {
          term->selanchor = term->selstart;
        }
      } else {
        /*
         * For rectangular selection, we have a choice of
         * _four_ places to put selanchor and selpoint: the
         * four corners of the selection.
         */
        if (2 * selpoint.x < term->selstart.x + term->selend.x)
          term->selanchor.x = term->selend.x - 1;
        else
          term->selanchor.x = term->selstart.x;

        if (2 * selpoint.y < term->selstart.y + term->selend.y)
          term->selanchor.y = term->selend.y;
        else
          term->selanchor.y = term->selstart.y;
      }
      term->selstate = DRAGGING;
    }
    if (term->selstate != ABOUT_TO && term->selstate != DRAGGING)
      term->selanchor = selpoint;
    term->selstate = DRAGGING;
    if (term->seltype == LEXICOGRAPHIC) {
      /*
       * For normal selection, we set (selstart,selend) to
       * (selpoint,selanchor) in some order.
       */
      if (poslt(selpoint, term->selanchor)) {
        term->selstart = selpoint;
        term->selend = term->selanchor;
        incpos(term->selend);
      } else {
        term->selstart = term->selanchor;
        term->selend = selpoint;
        incpos(term->selend);
      }
    } else {
      /*
       * For rectangular selection, we may need to
       * interchange x and y coordinates (if the user has
       * dragged in the -x and +y directions, or vice versa).
       */
      term->selstart.x = min(term->selanchor.x, selpoint.x);
      term->selend.x = 1 + max(term->selanchor.x, selpoint.x);
      term->selstart.y = min(term->selanchor.y, selpoint.y);
      term->selend.y = max(term->selanchor.y, selpoint.y);
    }
    sel_spread(term);
  } else if ((bcooked == MBT_SELECT || bcooked == MBT_EXTEND) &&
             a == MA_RELEASE) {
    if (term->selstate == DRAGGING) {
      /*
       * We've completed a selection. We now transfer the
       * data to the clipboard.
       */
      // region tray-url
      clipme(term,
             term->selstart,
             term->selend,
             (term->seltype == RECTANGULAR),
             FALSE,
             write_clip);
      // endregion
      term->selstate = SELECTED;
    } else
      term->selstate = NO_SELECTION;
  } else if (bcooked == MBT_PASTE && (a == MA_CLICK
#if MULTICLICK_ONLY_EVENT
                                      || a == MA_2CLK || a == MA_3CLK
#endif
                                      )) {
    request_paste(term->frontend);
  }

  /*
   * Since terminal output is suppressed during drag-selects, we
   * should make sure to write any pending output if one has just
   * finished.
   */
  if (term->selstate != DRAGGING)
    term_out(term);
  term_update(term);
}

int format_arrow_key(char *buf, Terminal *term, int xkey, int ctrl)
{
  char *p = buf;

  if (term->vt52_mode)
    p += sprintf((char *)p, "\x1B%c", xkey);
  else {
    int app_flg = (term->app_cursor_keys && !term->no_applic_c);
#if 0
	/*
	 * RDB: VT100 & VT102 manuals both state the app cursor
	 * keys only work if the app keypad is on.
	 *
	 * SGT: That may well be true, but xterm disagrees and so
	 * does at least one application, so I've #if'ed this out
	 * and the behaviour is back to PuTTY's original: app
	 * cursor and app keypad are independently switchable
	 * modes. If anyone complains about _this_ I'll have to
	 * put in a configurable option.
	 */
	if (!term->app_keypad_keys)
	    app_flg = 0;
#endif
    /* Useful mapping of Ctrl-arrows */
    if (ctrl)
      app_flg = !app_flg;

    if (app_flg)
      p += sprintf((char *)p, "\x1BO%c", xkey);
    else
      p += sprintf((char *)p, "\x1B[%c", xkey);
  }

  return p - buf;
}

void term_nopaste(Terminal *term)
{
  if (term->paste_len == 0)
    return;
  sfree(term->paste_buffer);
  term->paste_buffer = NULL;
  term->paste_len = 0;
}

static void deselect(Terminal *term)
{
  term->selstate = NO_SELECTION;
  term->selstart.x = term->selstart.y = term->selend.x = term->selend.y = 0;
}

void term_deselect(Terminal *term)
{
  deselect(term);
  term_update(term);

  /*
   * Since terminal output is suppressed during drag-selects, we
   * should make sure to write any pending output if one has just
   * finished.
   */
  if (term->selstate != DRAGGING)
    term_out(term);
}

int term_ldisc(Terminal *term, int option)
{
  if (option == LD_ECHO)
    return term->term_echoing;
  if (option == LD_EDIT)
    return term->term_editing;
  return FALSE;
}

int term_data(Terminal *term, int is_stderr, const char *data, int len)
{
  bufchain_add(&term->inbuf, data, len);

  if (!term->in_term_out) {
    term->in_term_out = TRUE;
    term_reset_cblink(term);
    /*
     * During drag-selects, we do not process terminal input,
     * because the user will want the screen to hold still to
     * be selected.
     */
    if (term->selstate != DRAGGING)
      term_out(term);
    term->in_term_out = FALSE;

    // region tray-url
    term->url_update = TRUE;
    // endregion
  }

  /*
   * term_out() always completely empties inbuf. Therefore,
   * there's no reason at all to return anything other than zero
   * from this function, because there _can't_ be a question of
   * the remote side needing to wait until term_out() has cleared
   * a backlog.
   *
   * This is a slightly suboptimal way to deal with SSH-2 - in
   * principle, the window mechanism would allow us to continue
   * to accept data on forwarded ports and X connections even
   * while the terminal processing was going slowly - but we
   * can't do the 100% right thing without moving the terminal
   * processing into a separate thread, and that might hurt
   * portability. So we manage stdout buffering the old SSH-1 way:
   * if the terminal processing goes slowly, the whole SSH
   * connection stops accepting data until it's ready.
   *
   * In practice, I can't imagine this causing serious trouble.
   */
  return 0;
}

/*
 * Write untrusted data to the terminal.
 * The only control character that should be honoured is \n (which
 * will behave as a CRLF).
 */
int term_data_untrusted(Terminal *term, const char *data, int len)
{
  int i;
  /* FIXME: more sophisticated checking? */
  for (i = 0; i < len; i++) {
    if (data[i] == '\n')
      term_data(term, 1, "\r\n", 2);
    else if (data[i] & 0x60)
      term_data(term, 1, data + i, 1);
  }
  return 0; /* assumes that term_data() always returns 0 */
}

void term_provide_logctx(Terminal *term, void *logctx)
{
  term->logctx = logctx;
}

void term_set_focus(Terminal *term, int has_focus)
{
  term->has_focus = has_focus;
  term_schedule_cblink(term);
}

/*
 * Provide "auto" settings for remote tty modes, suitable for an
 * application with a terminal window.
 */
char *term_get_ttymode(Terminal *term, const char *mode)
{
  const char *val = NULL;
  if (strcmp(mode, "ERASE") == 0) {
    val = term->bksp_is_delete ? "^?" : "^H";
  } else if (strcmp(mode, "IUTF8") == 0) {
    val = frontend_is_utf8(term->frontend) ? "yes" : "no";
  }
  /* FIXME: perhaps we should set ONLCR based on lfhascr as well? */
  /* FIXME: or ECHO and friends based on local echo state? */
  return dupstr(val);
}

struct term_userpass_state {
  size_t curr_prompt;
  int done_prompt; /* printed out prompt yet? */
  size_t pos;      /* cursor position */
};

/*
 * Process some terminal data in the course of username/password
 * input.
 */
int term_get_userpass_input(Terminal *term,
                            prompts_t *p,
                            const unsigned char *in,
                            int inlen)
{
  struct term_userpass_state *s = (struct term_userpass_state *)p->data;
  if (!s) {
    /*
     * First call. Set some stuff up.
     */
    p->data = s = snew(struct term_userpass_state);
    s->curr_prompt = 0;
    s->done_prompt = 0;
    /* We only print the `name' caption if we have to... */
    if (p->name_reqd && p->name) {
      size_t l = strlen(p->name);
      term_data_untrusted(term, p->name, l);
      if (p->name[l - 1] != '\n')
        term_data_untrusted(term, "\n", 1);
    }
    /* ...but we always print any `instruction'. */
    if (p->instruction) {
      size_t l = strlen(p->instruction);
      term_data_untrusted(term, p->instruction, l);
      if (p->instruction[l - 1] != '\n')
        term_data_untrusted(term, "\n", 1);
    }
    /*
     * Zero all the results, in case we abort half-way through.
     */
    {
      int i;
      for (i = 0; i < (int)p->n_prompts; i++)
        prompt_set_result(p->prompts[i], "");
    }
  }

  while (s->curr_prompt < p->n_prompts) {

    prompt_t *pr = p->prompts[s->curr_prompt];
    int finished_prompt = 0;

    if (!s->done_prompt) {
      term_data_untrusted(term, pr->prompt, strlen(pr->prompt));
      s->done_prompt = 1;
      s->pos = 0;
    }

    /* Breaking out here ensures that the prompt is printed even
     * if we're now waiting for user data. */
    if (!in || !inlen)
      break;

    /* FIXME: should we be using local-line-editing code instead? */
    while (!finished_prompt && inlen) {
      char c = *in++;
      inlen--;
      switch (c) {
      case 10:
      case 13:
        term_data(term, 0, "\r\n", 2);
        prompt_ensure_result_size(pr, s->pos + 1);
        pr->result[s->pos] = '\0';
        /* go to next prompt, if any */
        s->curr_prompt++;
        s->done_prompt = 0;
        finished_prompt = 1; /* break out */
        break;
      case 8:
      case 127:
        if (s->pos > 0) {
          if (pr->echo)
            term_data(term, 0, "\b \b", 3);
          s->pos--;
        }
        break;
      case 21:
      case 27:
        while (s->pos > 0) {
          if (pr->echo)
            term_data(term, 0, "\b \b", 3);
          s->pos--;
        }
        break;
      case 3:
      case 4:
        /* Immediate abort. */
        term_data(term, 0, "\r\n", 2);
        sfree(s);
        p->data = NULL;
        return 0; /* user abort */
      default:
        /*
         * This simplistic check for printability is disabled
         * when we're doing password input, because some people
         * have control characters in their passwords.
         */
        if (!pr->echo || (c >= ' ' && c <= '~') || ((unsigned char)c >= 160)) {
          prompt_ensure_result_size(pr, s->pos + 1);
          pr->result[s->pos++] = c;
          if (pr->echo)
            term_data(term, 0, &c, 1);
        }
        break;
      }
    }
  }

  if (s->curr_prompt < p->n_prompts) {
    return -1; /* more data required */
  } else {
    sfree(s);
    p->data = NULL;
    return +1; /* all done */
  }
}
